FPSO_Electric Motors Specification.pdf

8/11/2019 FPSO_Electric Motors Specification.pdf

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Shell Deepwater Development Systems, Inc. Doc. No. BONGA-SPEC-EE-003

Bonga Project September 17, 1999

Electric Motors Page 1 of 85

Specification Rev. B

R:\BONGA\CLERICAL\SPECS\EE\BONGA003(ELECTRIC MOTORS)

INDEX

SECTION TITLE PAGE

1.0 SCOPE 2

2.0 DESIGN AND ENGINEERING PRACTICE DEP 33.66.05.31 3

3.0 MODIFICATIONS TO DEP 33.66.05.31 83

APPENDIX A - Technical Data Sheets


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1.0 SCOPE

1.1 This Specification, together with the attachments and motor data sheets, covers Bongas requirements

for all electric motors for the facility. The Specification is based on Shells Design & EngineeringPractice DEP 33.66.05.31-Gen., Nov. 1995, Electric Motors: Cage-Induction and Synchronous Types.

The complete DEP is copied in Section 2.0 of this specification. Exceptions to the DEP, if any, are given

in Section 3.0.


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2.0 DESIGN ENGINEERING PRACTICE DEP 33.66.05.31

TECHNICAL SPECIFICATION

ELECTRIC MOTORS:

CAGE-INDUCTION AND SYNCHRONOUS TYPES

DEP 33.66.05.31-Gen.

November 1995

DESIGN AND ENGINEERING PRACTICE

This document is confidential. Neither the whole nor any part of this document may be disclosed to any third party without the prior written consent of Shell International Oil Products B.V. and

Shell International Exploration and Production B.V., The Hague, The Netherlands. The copyright of this document is vested in these companies. All rights reserved. Neither the whole nor any part

of this document may be reproduced, stored in any retrieval system or transmitted in any form or by any means (electronic, mechanical, reprographic, recording or otherwise) without the prior

written consent of the copyright owners.


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PREFACE

DEP (Design and Engineering Practice) publications reflect the views, at the time of publication, of:

Shell International Oil Products B.V. (SIOP)

and

Shell International Exploration and Production B.V. (SIEP)

and

Shell International Chemicals B.V. (SIC)

The Hague, The Netherlands,

and other Service Companies.

They are based on the experience acquired during their involvement with the design, construction, operation and maintenance of processing units and facilities, and

they are supplemented with the experience of Group Operating companies. Where appropriate they are based on, or reference is made to, national and international

standards and codes of practice.

The objective is to set the recommended standard for good design and engineering practice applied by Group companies operating an oil refinery, gas handling

installation, chemical plant, oil and gas production facility, or any other such facility, and thereby to achieve maximum technical and economic benefit from

standardization.

The information set forth in these publications is provided to users for their consideration and decision to implement. This is of particular importance where DEPsmay not cover every requirement or diversity of condition at each locality. The system of DEPs is expected to be sufficiently flexible to allow individual operating

companies to adapt the information set forth in DEPs to their own environment and requirements.

When Contractors or Manufacturers/Suppliers use DEPs they shall be solely responsible for the quality of work and the attainment of the required design and

engineering standards. In particular, for those requirements not specifically covered, the Principal will expect them to follow those design and engineering practices

which will achieve the same level of integrity as reflected in the DEPs. If in doubt, the Contractor or Manufacturer/Supplier shall, without detracting from his own

responsibility, consult the Principal or its technical advisor.

The right to use DEPs is granted by SIOP, SIEP or SIC, in most cases under Service Agreements primarily with companies of the Royal Dutch/Shell Group and other

companies receiving technical advice and services from SIOP, SIEP or SIC. Consequently, three categories of users of DEPs can be distinguished:

1) Operating companies having a Service Agreement with SIOP, SIEP, SIC or other Service Company. The use of DEPs by these Operating companies is

subject in all respects to the terms and conditions of the relevant Service Agreement.

2) Other parties who are authorized to use DEPs subject to appropriate contractual arrangements.

3) Contractors/subcontractors and Manufacturers/Suppliers under a contract with users referred to under 1) or 2) which requires that tenders for projects,

materials supplied or - generally - work performed on behalf of the said users comply with the relevant standards.

Subject to any particular terms and conditions as may be set forth in specific agreements with users, SIOP, SIEP and SIC disclaim any liability of whatsoever nature

for any damage (including injury or death) suffered by any company or person whomsoever as a result of or in connection with the use, application or implementation

of any DEP, combination of DEPs or any part thereof. The benefit of this disclaimer shall inure in all respects to SIOP, SIEP, SIC and/or any company affiliated to

these companies that may issue DEPs or require the use of DEPs.

Without prejudice to any specific terms in respect of confidentiality under relevant contractual arrangements, DEPs shall not, without the prior written consent of

SIOP and SIEP, be disclosed by users to any company or person whomsoever and the DEPs shall be used exclusively for the purpose for which they have been

provided to the user. They shall be returned after use, including any copies which shall only be made by users with the express prior written consent of SIOP and

SIEP. The copyright of DEPs vests in SIOP and SIEP. Users shall arrange for DEPs to be held in safe custody and SIOP or SIEP may at any time require information

satisfactory to them in order to ascertain how users implement this requirement.

All administrative queries should be directed to the DEP Administrator in SIOP.

NOTE: In addition to DEP publications there are Standard Specifications and Draft DEPs for Development (DDDs). DDDs generally introduce new procedures

or techniques that will probably need updating as further experience develops during their use. The above requirements for distribution and use of DEPs

are also applicable to Standard Specifications and DDDs. Standard Specifications and DDDs will gradually be replaced by DEPs.


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TABLE OF CONTENTS

1. INTRODUCTION.........................................................................................................7

1.1 SCOPE .........................................................................................................................71.2 DISTRIBUTION, INTENDED USE AND REGULATORY CONSIDERATIONS.............7

1.3 DEFINITIONS..............................................................................................................7

1.4 CROSS-REFERENCES ...............................................................................................13

2. GENERAL .................................................................................................................14

2.1 RESPONSIBILITY .....................................................................................................14

2.2 PRE-MANUFACTURING MEETING .........................................................................14

3. STATEMENT OF COMPLIANCE...............................................................................16

4. BASIC REQUIREMENTS...........................................................................................17

4.1 SITE CONDITIONS ...................................................................................................17

4.2 MOTOR RATINGS AND LIFECYCLE COST .............................................................17

4.3 DEGREE OF PROTECTION .......................................................................................194.4 METHODS OF COOLING ..........................................................................................19

4.5 TYPE OF CONSTRUCTION AND MOUNTING .........................................................20

4.6 EXCITATION SYSTEM .............................................................................................20

4.7 ELECTRICAL SUPPLY SYSTEM...............................................................................20

4.8 INFORMATION TO BE SUBMITTED WITH THE QUOTATION ...............................20

5. PERFORMANCE REQUIREMENTS...........................................................................21

5.1 STARTING, RESTARTING AND REACCELERATION ..............................................21

5.2 STARTING CHARACTERISTICS...............................................................................22

5.3 TRANSIENT AIR-GAP TORQUES .............................................................................24

5.4 RUNNING-UP TIME (RT) ..........................................................................................25

5.5 ALLOWABLE RUNNING-UP TIME (ART) ................................................................26

5.6 STALLING TIME.......................................................................................................27

5.7 TEMPERATURE LIMITATIONS................................................................................28

5.8 CRITICAL SPEEDS....................................................................................................29

5.9 VIBRATIONS ............................................................................................................30

5.10 NOISE CONTROL......................................................................................................32

5.11 PULSATING STATOR CURRENT .............................................................................33


5.13 UNIT TRANSFORMER ..............................................................................................35

6. CONSTRUCTION REQUIREMENTS .........................................................................36

6.1 MOTOR HOUSING ....................................................................................................36

6.2 ANTI-CONDENSATION HEATERS ...........................................................................38

6.3 WINDINGS ................................................................................................................39

6.4 TERMINAL BOXES...................................................................................................41

6.5 BUSHINGS AND TERMINALS..................................................................................436.6 ROTOR, FANS AND COUPLING ...............................................................................44

6.7 PROTECTIVE SYSTEMS...........................................................................................46

6.8 BEARINGS ................................................................................................................47

6.9 SPECIAL CONSTRUCTIONS.....................................................................................51

6.10 RATING PLATES ......................................................................................................52

6.11 MASS ........................................................................................................................53

6.12 SURFACE FINISH .....................................................................................................54


6.14 UNIT TRANSFORMER ..............................................................................................56

7. ADDITIONAL REQUIREMENTS FOR MOTORS IN ZONE 2 AREAS........................57


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7.1 GENERAL .................................................................................................................57

7.2 TEMPERATURE LIMITATIONS................................................................................57

7.3 FANS .........................................................................................................................57

7.4 AUXILIARY DEVICES ..............................................................................................577.5 CLEARANCES, SEPARATIONS AND CREEPAGE DISTANCES...............................57

7.6 RATING PLATE ........................................................................................................57

7.7 CERTIFICATE OF CONFORMITY.............................................................................58

8. ADDITIONAL REQUIREMENTS FOR MOTORS IN ZONE 1 AREAS........................59

8.1 TYPES OF PROTECTION AND TEMPERATURE LIMITATIONS..............................59

8.2 FANS .........................................................................................................................60

8.3 AUXILIARY DEVICES ..............................................................................................60

8.4 RATING PLATE ........................................................................................................60

8.5 CERTIFICATE OF CONFORMITY.............................................................................60

9. INSPECTION AND TESTS.........................................................................................61

9.1 PRODUCTION TESTS ...............................................................................................61

9.2 FINAL TESTS ............................................................................................................639.3 TEST SPECIFICATION..............................................................................................64

9.4 TOLERANCES ON PERFORMANCE VALUES ..........................................................68

10. DOCUMENTS............................................................................................................69

10.1 GENERAL .................................................................................................................69

10.2 MANUFACTURER'S TECHNICAL INFORMATION ..................................................69

10.3 TEST REPORTS.........................................................................................................69

11. REFERENCES............................................................................................................70

APPENDICES

APPENDIX 1 INSULATION QUALITY TESTS ......................................................................74

APPENDIX 2 VIBRATION TESTS .........................................................................................76

APPENDIX 3 MINIMUM EXPECTED FULL LOAD EFFICIENCY OF MOTORS ....................77

APPENDIX 4 MINIMUM EXPECTED FULL LOAD POWER FACTOR OF MOTORS .............79

APPENDIX 5 EXAMPLE OF ALL-IN COST CALCULATION.................................................81


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1. INTRODUCTION

1.1 SCOPE

This DEP specifies the technical requirements for electric motors of the cage-induction andsynchronous types. This DEP is a revision of the previous publication of the same number dated

February 1990.

Motors shall comply with IEC 34 except as amended and supplemented by this DEP.

NOTES: 1. A bullet () in the margin indicates where a decision by, and/or information from, the Principal isrequired. These decisions and this information will be indicated in the requisition.

2. An asterix (*) in the margin indicates where design alternatives may be acceptable. In certain cases these

alternatives are subject to approval by the Principal.

3. A diamond () in the margin indicates where information from the Manufacturer is required. Thisinformation shall be indicated in the requisition.

The minimum performance requirements specified in this DEP refer to constant speed operation

and direct-on-line starting of the motors. For variable speed drives, DEP 33.66.05.33-Gen. shall

also apply.In case of conflict between documents relating to the enquiry/order the following priority of

documents shall apply:

1. purchase order;

2. requisition and project specification;

3. this DEP.

SI units shall be used throughout.

1.2 DISTRIBUTION, INTENDED USE AND REGULATORY CONSIDERATIONS

Unless otherwise authorised by SIOP and SIEP, the distribution of this DEP is confined to

companies forming part of or managed by the Royal Dutch/Shell Group. It may be distributed to

Contractors and Manufacturers/Suppliers nominated by them (i.e. the distribution code is "F", as

defined in DEP 00.00.05.05-Gen.).

This DEP is intended for use in oil refineries, chemical plants, gas plants, exploration and

production facilities and supply/marketing installations.

If national and/or local regulations exist in which some of the requirements may be more stringent

than in this DEP, the Contractor shall determine by careful scrutiny which of the requirements are

the more stringent and which combination of requirements will be acceptable as regards safety,

economic and legal aspects. In all cases the Contractor shall inform the Principal of any deviation

from the requirements of this document which is considered to be necessary in order to comply

with national and/or local regulations. The Principal may then negotiate with the Authorities

concerned with the object of obtaining agreement to follow this document as closely as possible.

1.3 DEFINITIONS

1.3.1 General definitions

The Contractoris the party which carries out all or part of the design, engineering, procurement,

construction, commissioning or management of a project or operation of a facility. The Principal

may undertake all or part of the duties of the Contractor.

TheManufacturer/Supplieris the party which manufactures or supplies equipment and services

to perform the duties specified by the Contractor.

The Principalis the party which initiates the project and ultimately pays for its design and

construction. The Principal will generally specify the technical requirements. The Principal may

also include an agent or consultant, authorised to act for, and on behalf of, the Principal.


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The word shallindicates a requirement.

1.3.2 Specific definitions

Accelerating torque, IEC 50: 411-18-06The difference between the electromagnetic starting torque and the total load torque, available foraccelerating the rotating parts.

Air-to-air cooled machine

A closed machine with integral or machine mounted heat exchanger, using air as the primary and

secondary coolant.

NOTE: The most commonly used cooling methods are coded IC5A1A1, IC6A1A1 and IC6A6A1 in accordance with IEC

34-6.

Air-to-water cooled machine

A closed machine with a heat exchanger using air as primary coolant and water as secondary

coolant.

NOTE: The most commonly used cooling methods are coded IC8A1W7 and IC8A7W7 in accordance with IEC 34-6.

Allowable running-up time (ART)The time for a motor to complete one start with rated voltage and frequency applied and coupled to

a load with the actual running-up characteristics, but with the maximum moment of inertia so that

when full speed is reached the most critical part of the motor has reached the highest permissible

temperature.

The initial motor temperature is to be its full load working temperature. The coolant temperature is

to be the maximum specified.

Asynchronous machine, IEC 50: 411-01-07

An alternating current machine in which the speed on load and the frequency of the system to

which it is connected are not in a constant ratio.

Breakdown torque (of an AC motor), IEC 34-1

The maximum value of the steady-state asynchronous torque which the motor develops without an

abrupt drop in speed, when the motor is supplied at the rated voltage and frequency.This definition does not apply to those asynchronous motors of which the torque continually

decreases with increase in speed.

Cage induction motor,IEC 50: 411-03-15

An induction motor in which a primary winding on one member, usually the stator. is connected to

the power source, and a secondary cage winding on the other member, usually the rotor, carries

induced current.

Capital Charges

The Capital Charge is a means of expressing a once off expenditure in the form of a cost per unit

of time or quantity over the assumed lifetime of the asset i.e motor. It represents the required net

cash flow in real terms before tax to cover e.g. return on capital, payment of tax and inflation.

These are dependent on local circumstances and can be obtained from e.g. the refinery economist.

CertificateDocument issued by a recognised authority certifying that it has examined a certain type of

apparatus and, if necessary, has tested it and concluded that the apparatus complies with the

relevant standard for such apparatus.

Certificate of conformity

Certificate stating that the electrical apparatus complies with the relevant standards for apparatus

for potentially explosive atmospheres.

Coastal installation

An installation located within 1 km of open saliferous water. This may include jetties etc. that

project into the water.

Continuous running duty - Duty type S1 IEC 50: 411-21-14


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Operation at constant load of sufficient duration for thermal equilibrium to be reached.

Critical speed

If resonance exists at a finite speed, that speed is called a critical speed, irrespective of the cause of

the resonance.NOTE: A critical speed can be caused by a number of reasons like electrical/magnetic asymmetry, oil whirl or torsion between

shaft components.

Declaration of complianceIEC 79-15

Document issued by the Manufacturer declaring that the electrical apparatus complies with the

requirements of IEC 79-15.

NOTE: The declaration of compliance, which is a document officially recognised in IEC 79-15, only refers to the specific

requirements applicable to machines for use in Zone 2 areas.

Disc and wiper lubricated bearingIEC 50: 411-12-15

A bearing in which a disc mounted on and concentric with the shaft dips into a reservoir of oil. As

the shaft rotates, the oil is diverted from the surface of the disc by a scraper action onto the

bearing.

DutyIEC 50: 411-21-07

Statement of the load, including no load and rest and de-energised periods to which the machine is

subjected, including their duration and sequence in time.

Expected lifetime

The expected lifetime of a motor is the time during which the motor remains suitable for the

application for which it was made when regularly inspected, examined and serviced in accordance

with the Manufacturers instructions, with replacement of lubricants and of parts subject to wear.

Forced lubricated bearingIEC 50: 411-12-18

A bearing in which a continuous flow of lubricant is forced over the bearing or journal.

NOTE: For electric machines the inlet pressure of the forced lubricated bearing will normally range from 1.2 to 1.5 x 105Pa.

Frame-surface cooled machine

A closed machine with its surface cooled by means of surrounding medium.

NOTE: The surface may be plane or ribbed. The most commonly used cooling method is coded IC4A1A1 in accordance with

IEC 34-6.

Full loadIEC 34-1

The highest value of load specified for a machine operating at rated output.

Full load powerIEC 34-1

The highest value of power specified for a machine operating at rated output .

NOTE: This concept also applies to torque, current, speed, etc.

Hazardous area IEC 79-10

An area in which an explosive gas atmosphere is present, or may be expected to be present, in

quantities such as to require special precautions for the construction, installation and use of

electrical apparatus.

Induction machineIEC 50: 411-01-09

An asynchronous machine comprising of a magnetic circuit interlinked with two or more electric

circuits moving relative to one another and in which power is transferred from the stationary to the

moving part, or vice versa, by electromagnetic induction.

NOTE: In many countries this term is practically synonymous with asynchronous machine, whereas some others recognise

only the term "asynchronous machine" for both concepts.

Land installation

An installation located at sufficient distance from open saliferous water to minimise the effects of a

salt laden atmosphere.

Limiting temperature IEC 79-7

Maximum permissible temperature for apparatus or parts of apparatus equal to the lower of the two

temperatures determined by:

- The danger of ignition of the explosive gas atmosphere.


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- The thermal stability of the materials used.

NOTE: This temperature may be the maximum surface temperature or a lower value.

Locked rotor current IEC 34-1

The measured steady-state root-mean-square current taken from the line with the rotor locked withrated voltage and frequency applied.

Locked rotor torque IEC 50: 411-18-02

The minimum measured torque which the motor will develop with the rotor locked and rated

voltage applied at rated frequency.

Low voltage (LV)

A voltage not exceeding 1000 V.

Moment of inertiaIEC 34-1

The (dynamic) moment of inertia of a body about an axis is the sum (integral) of the products of its

mass elements and the squares of their distances (radii) from the axis.

NOTE: This quantity is designated by the letter Jand is expressed in kg m2.

Non-hazardous areaIEC 79-10

An area in which an explosive gas atmosphere is not expected to be present in quantities such as to

require special precautions for the construction, installation and use of electrical apparatus.

Non-sparking apparatus

Apparatus meeting the requirements of a recognised standard for industrial equipment which in

normal service does not arc or spark or produce ignition-capable hot surfaces.

Offshore installation

An installation located in open saliferous water, at a location remote from the nearest land.

Oil ring lubricated bearingIEC 50: 411-12-14

A bearing in which a ring, encircling the journal and rotated by it, raises the oil to lubricate the

bearing from a reservoir into which the ring dips.

Output (power)IEC 50: 411-21-04The useful mechanical power measured at the shaft-end of a motor.

Pull-in torqueIEC 50: 411-18-08

The maximum torque against which a synchronous motor will pull its connected load into

synchronism at rated voltage and frequency, when the field excitation, if used, is applied.

NOTE: The pull-in torque depends on the total inertia of the rotating parts.

Pull-out torque (of a synchronous motor)IEC 34-1

The maximum torque which the synchronous motor develops at operating temperature and at

synchronous speed with rated voltage, frequency and field current.

Pull-up torque (of an AC motor)IEC 34-1

The smallest value of the steady-state asynchronous torque which the motor develops between zero

speed and the speed which corresponds to the breakdown torque, when the motor is supplied at the

rated voltage and frequency.

This definition does not apply to those asynchronous motors of which the torque continuallydecreases with increase in speed.

NOTE: In addition to the steady-state asynchronous torques, harmonic synchronous torques, which are a function of rotor load

angle, will be present at specific speeds.

At such speeds the accelerating torque may be negative for some rotor load angles.

Experience and calculation show this to be an unstable operation condition and therefore harmonic synchronous torques do not

prevent motor acceleration and are excluded from the definitions.

Rated output IEC 34-1

The rated output is the mechanical power available at the shaft and shall be expressed in watts

(W).

NOTE: It is practice in many countries for the mechanical power available at the shafts of motors to be expressed also in

horsepower (1 hp is equivalent to 745.7 W, 1 ch (cheval or metric horsepower) is equivalent to 736 W).


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Rated voltageIEC 34-1

The rated voltage is the voltage between lines at the terminals of the machine at rated output.

Rated load torqueIEC 50: 411-18-01

The shaft torque of a motor corresponding to rated output and speed.

RatingIEC 50: 411-21-22

The whole of the numerical values of the electrical and mechanical quantities with their duration

and sequences, assigned to the machine by the Manufacturer and stated on the rating plate, the

machine complying with the specified conditions.

NOTE: The duration may be indicated by a qualifying term.

Requisition

Therequisition is the information exchanged between the Principal and the Manufacturer prior to

order placement, using requisition form DEP 33.66.05.93-Gen. and, if necessary, the blank

requisition form DEP 30.10.00.94-Gen.

Room temperatureIEC 894The reduced range standard ambient (18 C to 28 C) stated in footnote 5 of Table I of IEC Publication 212.

Running-up time (RT)The time for a motor to complete one start with rated voltage and frequency applied and coupled to

the actual load.

Self-cooled machine

A machine where the cooling is obtained by means of its own rotation.

Separately-cooled machine

A machine where the cooling is obtained by other means than its own rotation.

Site conditions

The external factors, e.g. altitude, air temperature, wind velocity, vibrations, earthquakes, relative

humidity, voltage and frequency variations etc., which may influence the operation of a machine.

Spherical seated bearingIEC 50: 411-12-22

A journal bearing in which the bearing liner is supported in such a manner as to permit the axis of

the journal to be moved through an appreciable circular angle.

Stalling time

The time taken for any part of the motor, when the motor is energised at rated voltage and in the

stalled condition, to be heated up from the temperature reached under full load and maximum

coolant temperature conditions to the highest temperature which does not impair its subsequent

performance.

Starting current IEC 50: 411-18-19

The root mean square current drawn by the motor during the starting period.

NOTE: This current is not a single value and the complete current-speed curve of the motor is needed to express it.

Starting load torque

The torque required by the load over the starting period from zero speed to load speed.

NOTE: The starting torque includes, if applicable, compression torque and bearing friction torque.

Starting torqueIEC 50: 411-18-05

The electromagnetic torque exerted by a motor during the starting period.

Synchronous machine IEC 50: 411-01-06

An alternating current machine in which the frequency of the generated voltage and speed of the

machine are in a constant ratio.

Thermal equilibriumIEC 50: 411-21-09

The state reached when the observed temperature-rises of the several parts of the machine do not

vary any longer.

NOTE: In practice, equilibrium is assumed to be reached when the temperature does not vary over a period of one hour by

more than a specified amount, e.g. 2K.


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Time te

The time teis the lesser of the times defined below:

- For the AC windings, when carrying the locked rotor current with the motor in the stalled

condition, to be heated up, from the temperature reached under full load and maximum coolant

temperature conditions, to the limiting temperature.

- For any other part of the motor in stalled condition, and with the AC windings carrying the

locked rotor current, to be heated up, from the temperature reached under full load and maximum

coolant temperature conditions, to the limiting temperature.

Type of protection 'd' IEC 79-1

A type of protection of electrical apparatus in which the enclosure will withstand an internal

explosion of a flammable mixture which has penetrated into the interior, without suffering damage

and without causing ignition, through any joints of structural openings in the enclosure, of an

external explosive atmosphere consisting of one or more of the gases or vapours for which it is

designed.

Type of protection 'e'IEC 79-7

Type of protection applied to electrical apparatus that does not produce arcs or sparks in normalservice, in which additional measures are applied so as to give increased security against the

possibility of excessive temperatures and of the occurrence of arcs and sparks.

Type of protection 'n'IEC 79-15

A type of protection applied to electrical apparatus such that, in normal operation, it is not capable

of igniting a surrounding explosive gas atmosphere and a fault capable of causing ignition is not

likely to occur.

Type of protection 'p'IEC 79-2

The concept of achieving safety by means of a protective gas.

Type tests IEC 50: 411-13-02

The performance tests taken on one of the first machines of each type of design.

UnIEC 894

The rated rms phase-to-phase voltage by which the system is designated and to which certain

operating characteristics of the system are related.

Vibration severityISO 2372

The vibration severity is the root-mean-square value of the vibration velocity.


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1.4 CROSS-REFERENCES

Where cross-references to other parts of this DEP are made, the referenced section number is

shown in brackets. Other documents referenced by this DEP are listed in (11).


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2. GENERAL

2.1 RESPONSIBILITY

The order for an electric motor in accordance with this DEP may be placed directly with the motormanufacturer, or via the manufacturer of the driven equipment. In the latter case the Principal will

inform the manufacturer of the driven equipment of approved manufacturers from which motors

may be purchased.

* The motor and driven equipment shall be assembled at the factory of the driven equipment

manufacturer. If this is not practical the Manufacturer shall request permission from the Principal

to assemble the motor and driven equipment at the destination site.

The driven equipment manufacturer shall, primarily, be responsible for the operation to

specification of the combination of motor and driven equipment.

The motor manufacturer shall supply to the driven equipment manufacturer all the information

necessary to enable him to comply with his responsibilities.

Special attention shall be paid to information relevant for correct design of the lubrication system,

mechanical shaft system, coupling and foundation of the equipment.

Unless otherwise stated in the requisition the motor manufacturer shall include the following itemson the motor:

At tender:

- Mass of motor (kg)

- Moment of inertia 'J' (kg m2)

- Lubrication requirements in case of force-lubricated bearings

On receipt of order:

- Calculated critical speed(s) (1/min)

- Transient air-gap torque plots:with two and three-phase short-circuit at the motor terminals, and with

their respective frequencies over a 200 ms time period (Nm)- Stalling times, hot and cold (s)

- Running-up times

- Dynamic model of motor to enable accurate flywheel sizing forreciprocating loads and recommended flywheel size

- Rotor residual voltage time-constants and transient air-gap torques onreconnection after power interruption

- Heating/cooling time constants for thermal replica protection

- Maximum tolerable axial force (see 6.8.4)

- Thermal endurance graphs showing insulation life versus temperatures inthe range including classes B and F; such results shall be based on actual

coils employing the Manufacturer's insulation system, tested to IEEE 117or IEEE 275 as appropriate.

At testing:

- Severity of multiples of the supply frequency present in the vibration

spectrum2.2 PRE-MANUFACTURING MEETING

If deemed necessary a pre-manufacturing meeting shall be arranged with all parties concerned.This will be stated in the requisition or may be initiated later by the Manufacturer.


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The purpose of this meeting is to define the scope and parameters of the order and the

responsibilities of each party involved. The final list of deviations to this DEP shall be agreed.

Agreement shall be reached with respect to administrative, production and test procedures.


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3. STATEMENT OF COMPLIANCE

The Manufacturer shall guarantee that the equipment complies with the quotation and is properly

designed, constructed and suitable for the specified use. The equipment shall be tested at the

Manufacturer's works to prove its capability and compliance with this DEP. Tolerances shall be in

accordance with this DEP.


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4. BASIC REQUIREMENTS

This DEP covers cage-induction and synchronous motors, and auxiliary equipment. The

requisition shall be supplied with each enquiry to specify the requirements and deviations (if

applicable) from this DEP.

The motor and all individual items forming part of the motor, including, if applicable, the unit

transformer, shall comply with sound engineering practices which shall result in an expected

lifetime of minimum 20 years and shall be suitable for at least 4 years of uninterrupted operation

under the conditions specified. Rolling element bearings are exempted from the expected lifetime

requirement.

The motor shall be designed for continuous running duty type S1, according to IEC 34-1, and shall

be suitable for the load characteristics and operational duty of the driven equipment. Periods of

running may alternate with idle (standstill) periods of maximum 6 months. At the end of such an

idle period the motor shall, without requirement for additional inspection, be suitable for another

running period.

The unit transformer of the motor, if applicable, shall meet the requirements of the motor-

transformer combination as specified in this DEP and DEP 33.65.40.31-Gen. If the motor is part of

an Electrical Variable Speed Drive System, this DEP and DEP 33.66.05.33-Gen. shall apply.

4.1 SITE CONDITIONS

The motor and all individual items forming part of the motor shall be suitable for use outdoors

without protective shelter. The atmosphere is to be considered saliferous, sulphurous and dusty, as

commonly encountered in oil or chemical installations located close to open water. The possibility

of condensation, as experienced during large temperature fluctuations in humid atmosphere, shall

be taken into account separately under 6.2 and 6.13.

The requisition specifies the site conditions. Where these are not specified, it is deemed that thePrincipal accepts the following default conditions and the financial consequences thereof.

- exposure to direct sunlight : Yes

- maximum ambient air temperature : 40 C

- minimum ambient air temperature : -15 C

- maximum cooling water inlet temperature : 30 C

- minimum cooling water inlet temperature : 5 C

- maximum static water pressure : 8x105Pa

- minimum static water pressure : 3x105Pa

- altitude not exceeding : 1000 m

- relative humidity : 90%

- maximum wind velocity for offshore installations : 45m/s

- maximum shocks experienced on offshore installations : 20 m/s2

- maximum vibration expected from adjacent operating

equipment with the motor running or standing idle

: 0.4 mm/s (rms)

NOTE: The default ambients are chosen to coincide with those specified in IEC-34-1. The maximum ambient air temperature

of 40 C is taken to be the 'Mean Annual Extreme' as defined in IEC 721-2-1 for a warm, damp climate. For HV

motors the Principal may select the 'Mean Annual Extremes' which correlate with their site statistics; 'Absolute

Extremes' shall not be selected.

4.2 MOTOR RATINGS AND LIFECYCLE COST

4.2.1 Ratings

The required motor rating and speed will be stated in the requisition.


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The rating of the machine offered by the Manufacturer shall be in accordance with IEC 72 Part 1

and 2 and be based on class F insulation used to class B temperature rise.

* The minimum expected values for efficiency and power factor of cage-induction motors rated up

to 1000 kW are provided in Appendices 3 and 4, respectively. Cage-induction motors rated atmore than 1000 kW and synchronous motors shall have efficiencies and power factors not less than

those indicated in the following table.

Type of motor voltage efficiency (%) power factor

2-pole 4-pole 2-pole 4-pole

Cage induction > 1000 kW HV 96.5 96.6 0.91 0.88

Synchronous HV 98 97.5 NA NA

The above values are related to full load operation of the motor.

For synchronous motors the values are related to full load operation at a power factor 0.9 leading

and include the power consumption of the excitation system.

While reliable operation is of first importance, motors which also offer high efficiency and powerfactor at both full and three-quarter loads will be preferred. If the Manufacturer has units in higher

efficiency ranges, then he shall also offer such ranges as alternatives.

For motors which require separately driven auxiliary devices, like ventilators for method ofcooling IC6A6A1, the Manufacturer shall list the power consumption of these devices.

4.2.2 Lifecycle cost

If stated in the requisition, the Manufacturer shall submit a calculation which enables the Principalto compare the Total All-in Cost (TAC) per annum of the motors offered, using the formula given

below, and using the factors and cost data stated in the requisition:

+

+

= mancostman

otapc

PF

MDC12

E8760E

KP

100

CC

TAC

where: C = Capital Expenditure

Capc = Capital Charge (%)

P = rated output motor (kW)

Kot = operating time per annum (%). Typically 100% for a single motor

application and 50% for dual motors.

Eman = efficiency value guaranteed by the Manufacturer (%)

Ecost = energy unit cost (cost/kWh)

MDC = maximum demand charge per month (cost/kVA)

PFman = power factor value guaranteed by the Manufacturer

An example of the calculation is given in Appendix 5.


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4.3 DEGREE OF PROTECTION

The degree of protection (to IEC 529) shall be at least:

for land and coastal installations:IP 54 for the motor and auxiliariesIP 55 for the terminal boxes and bearing housings

for offshore installations IP 56 for the motor, auxiliaries, terminal boxes and

bearing housings.

for submerged electric motors and

electric drives of seal-less pumps:

IP 68 for the applicable parts

NOTE: For large machines, especially low speed motors, a lower degree of protection, e.g. IP 44, may be acceptable if

approved by the Principal. Terminal boxes and bearing housings shall always have a degree of protection of at least IP

55.

The enclosure of the motor shall be equipped with a normally open drain hole in accordance with

IEC 34-5 to IP 44. Attention shall be paid to the correct location of the drain hole, especially forvertical motors.

The sealing of bearing housings, especially for vertical motors with upwards drive-end shaft,

mounting arrangement IM V3 (IM 3031) and IM V6 (IM 1031) according to IEC 34-7, shall be

such that no water can penetrate the motor via the shaft. Collection of water and dirt on the upper

bearing endshield shall have no negative effects on the performance or lifetime of the motor.

Vertical motors with a downward drive-end shaft shall be provided with a rain canopy covering the

air inlet of the fan cowl.

4.4 METHODS OF COOLING

Unless otherwise specified, motors shall be frame-surface or air-to-air, self-cooled machines with

method of cooling IC 4A1A1, IC 5A1A1 or IC 6A1A1 according to IEC 34-6.

If specified in the requisition, air-to-water, self-cooled machines with cooling method IC 8A1W7shall be supplied according to IEC 34-6.

* Separately cooled machines are only allowed for special applications and with the approval of the

Principal. Attention shall be paid to sparing of auxiliaries of separately cooled machines.

* The cooling air for the exciter of a synchronous motor shall be taken from the cooling air circuit of

the motor via ducting; method of cooling IC 31. For exciters where this method of cooling is no

longer practical the cooling of the exciter shall be independent of the motor. In these situations the

method of cooling shall be IC 6A1A1 or IC 8A1W7.

For air-to-water coolers the following design data apply:

- maximum cooling water outlet temperature : 37 C

- maximum temperature rise of the cooling water : 7 K

- minimum cooling water velocity in tubes : 1 m/s

- fouling resistance : 0.52x10-3m 2K/W

The coolers shall be pressure-tested at 1.5 times the maximum working pressure for 15 minutes to

demonstrate the withstand capability. If the water pressure in the cooler is controlled by a valve or

pressure-reducing device connected to a water supply of higher pressure than the working pressure

of the cooler, the cooler shall be designed for the higher pressure, and tested at 1.5 times the higher

pressure value.

The Principal shall submit to the Manufacturer the relevant data regarding the cooling water.


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4.5 TYPE OF CONSTRUCTION AND MOUNTING

The type of mounting for standard motors shall be IM B3 (IM 1001), IM B5 (IM 3001), IM V1

(IM 3011) or IM V6 (IM 1031) according to IEC 34-7.

However, for special applications, like reciprocating compressor drives, a different type of

mounting may be preferred.

The general characteristics of the type of mounting required will be indicated in the requisition.Frame sizes shall be in accordance with IEC 72 Part 1 and 2.

Dimensions of foot-mounted motors and mounting flanges of motors shall be in accordance with

IEC 72 Part 1 and 2.

4.6 EXCITATION SYSTEM

The exciter shall consist of a brushless three phase synchronous generator, rotating rectifier

assembly and, if applicable, a pilot exciter. Field protective, application and shorting functions

shall be accomplished by solid-state control. The Manufacturer shall supply the motor excitation

panel which will be installed adjacent to the Principal's switchgear.

4.7 ELECTRICAL SUPPLY SYSTEM

The rated values of the supply voltage, frequency, minimum and maximum fault level at the motorterminals will be stated in the requisition.

Motors shall be suitable for operation on a supply voltage having a harmonic content and

unbalance as specified in IEC 34-1.

Motors shall be capable of performing their primary function within the voltage and frequency

variations as stated in IEC 34-1. The permissible temperature rise under these conditions is stated

in IEC 34-1.

The motors shall be suitable to operate:

- continuously on an unearthed system.

- for periods of up to 8 hours on an unearthed system with an earth fault on one phase. The

maximum cumulative number of hours of operation in this mode will be restricted to 125 per year.

As a result of switching activities in the supply system, steep fronted transient voltage waves can

be expected at the terminals of HV motors.

4.8 INFORMATION TO BE SUBMITTED WITH THE QUOTATION

By submitting the quotation the Manufacturer is deemed to have agreed to comply with this DEPand the requisition.

* If the Manufacturer has any deviations, concerning both requirements and recommendations,these shall be identified in writing at the time of the quotation.

Deviations from the requirements shall always require approval from the Principal statingspecifically the approved deviation.

For documents to deliver with the quotation refer to (10.2).

The motor manufacturer shall state in the quotation the country of origin of the main parts of themotor.

For maintenance and overhaul at site, the Manufacturer shall indicate the nearest service

organisation recommended for the location at which the motor will be installed.


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5. PERFORMANCE REQUIREMENTS

5.1 STARTING, RESTARTING AND REACCELERATION

5.1.1 General

Motors shall be suitable for direct-on-line asynchronous starting.

Cage-induction motors shall be suitable for restart under full load conditions and at any voltage

between 80% and 100% of the rated voltage applied at the motor terminals.

It may be assumed that the power interruption will not exceed 0.2 seconds and that the driven

equipment exhibits a quadratic torque-speed characteristic.

* If the Manufacturer cannot meet this requirement he shall, in the quotation, provide detailed

information regarding the limiting factors in the motor design.

For constant-torque loads, the Manufacturer shall indicate if a minimum flywheel is required toensure successful reacceleration ability of the motor in the event of a power interruption of 0.2 sec.

Where such a flywheel is not provided, the Manufacturer shall provide in the quotation detailedinformation regarding the reacceleration ability of the motor with respect to voltage drop in

combination with time.

For motors which are supplied via a dedicated unit transformer, different requirements mayprevail. In these situations the design of the motor-transformer combination shall be optimised with

respect to maximum allowable voltage drop at the supply busbar and start/restart performance of

the motor.

5.1.2 Number of sequential starts

At any voltage between 80% and 100% rated voltage, motors (including their unit transformers, if

applicable) shall be capable of:

- three successive starts with the motor initially at maximum ambient temperature;

- two successive starts with the motor initially at full load operating temperature.

Between successive starts the motor will decelerate under operating conditions.

After a cooling period of 30 minutes at standstill, another starting sequence of at least two

successive starts shall be possible.

* For motors with a rated output in excess of 1600 kW, deviations from this requirement may be

acceptable. However, approval to deviate shall be obtained from the Principal.

* For motors with a rated output in excess of 1600 kW, and especially for synchronous machines, the

Manufacturer may separately quote their standard-start option.

Unless otherwise agreed with the Principal, the load torque shall be as specified in 5.2.3.

5.1.3 Number of starts per year

Motors including, if applicable, the unit transformer shall be suitable for one of the duties listedbelow:

Normal : maximum 1000 starts per year

Heavy : maximum 3000 starts per year, e.g. conveyer systems, drain pumps,

etc.

Extra heavy : maximum 20 000 starts per year, e.g. hoisting equipment, cranes, etc.


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5.2 STARTING CHARACTERISTICS

The requirements related to the motor torque capabilities, as described in this section, are all based

on a situation where the motor is at full load operating temperature and with rated voltage and

frequency applied, unless otherwise stated.

5.2.1 Starting current

For LV motors the maximum value of locked rotor apparent power shall comply with IEC 34-12.

However, for motors with a rated output in excess of 55 kW, the starting current shall not exceed

7.0 times the rated current of the motor.

For HV motors the starting current shall not exceed 6.5 times the rated current of the motor.

More stringent limitations, if applicable, will be specified in the requisition.

5.2.2 Starting performance

The starting performance of LV motors shall comply with IEC 34-12. Unless otherwise stated inthe requisition, driven equipment with a quadratic torque-speed characteristic shall be of design Nwhile the other torque-speed characteristics shall be of design H.

* The starting performance of HV cage-induction motors should be not less than the values listed in

the table below:

rating number of poles

(kW) 2 4 6

Tl Tu Tb Tl Tu Tb Tl Tu Tb

100 to 250 0.8 0.6 1.8 0.9 0.7 1.8 0.9 0.7 1.8

280 to 500 0.7 0.6 1.8 0.7 0.6 1.8 0.7 0.6 1.8

560 to 1600 0.6 0.5 1.8 0.6 0.5 1.8 0.6 0.5 1.8

above 1600 to be agreed by the Principal

All values are per unit values based on the rated torque.

Tl= locked rotor torque

Tu= pull-up torque

Tb= breakdown torque

5.2.3 Motor torque-speed characteristic

The torque-speed characteristic of the motor with rated frequency and 80% rated voltage applied atthe motor terminals shall be adequate for starting the driven load under the most severe conditions,

e.g. pump with open discharge. Under these conditions the accelerating torque shall not be less

than 10% of the load full torque.

* The above applies for driven equipment which exhibits a quadratic torque-speed characteristic; forother types of driven equipment or for motors with a rated output in excess of 1600 kW it may not

be possible to comply with this requirement. For these situations the start conditions shall be

discussed with the Principal.

The locked rotor torque with 80% rated voltage and rated frequency applied at the motor terminals

shall be more than 30% of the rated torque.


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* When motors are supplied via a dedicated unit transformer, the design of the motor-transformer

combination shall be optimised such that the locked rotor torque, with the resultant voltage at the

motor terminals, is more than 30% of the rated torque. When it is not possible to comply with this

requirement, the start conditions shall be discussed with the Principal.

5.2.4 Breakdown torque for cage-induction motors

The breakdown torque shall not exceed 300% of the rated torque and shall be higher than 180% of

the rated torque.

5.2.5 Pull-out torque for synchronous motors

The pull-out torque shall be in excess of 135% of the rated torque for cylindrical rotor motors and

in excess of 150% of the rated torque for salient pole motors.

5.2.6 Pull-in torque for synchronous motors

The pull-in torque shall be at least 60% of the rated torque for two, four and six-pole machines.

For machines with a pole number of eight and higher the pull-in torque shall be at least 45% of the

rated torque.


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5.3 TRANSIENT AIR-GAP TORQUES

All motors shall cater for three-phase short-circuit currents with respect to their end winding

supports. Their shaft and active iron core systems shall cater for two-phase short-circuits.

Unless the Principal confirms that the starter arrangement specifically reduces reconnection

torques, cage-induction motors shall be suitable for restart with full residual voltage. In this

respect, the Manufacturer shall ensure that the endwinding supports are suitable for supply

reconnection onto full motor residual voltage at total phase opposition, and that the shaft and

active iron core systems are suitable for supply reconnection onto full motor residual voltage at

120 degree phase difference.

NOTE: Where the Manufacturer cannot readily calculate the above quantities other than rated and three-phase short-circuit

torques, the following assumptions may be made. The two-phase short-circuit torque is 1.2 times the three-phase

short-circuit torque. The 180 degree reconnection will result in an endwinding current 20 times the rated current. The

120 degree reconnection will result in a reconnection torque 2.6 times the three-phase short-circuit torque. Particular

attention shall be paid to the translation from air-gap to shaft/coupling torques in the case of high-inertia loads; this

will require close liaison with the driven equipment manufacturer.

For HV cage-induction motors the Manufacturer shall state the maximum transient air gap torquein case of:

- two and three-phase short-circuit at the motor terminals;

- reconnection after power interruption.

For synchronous motors the Manufacturer shall state the maximum transient air gap torquesduring:

- asynchronous start;

- two and three-phase short-circuit at the motor terminals;

- reconnection after power interruption.


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5.4 RUNNING-UP TIME (RT)

The Manufacturer shall state the running-up time at 80% and 100% rated voltage applied at themotor terminals.

For cage-induction motors up to and including 660 V the initial value of the external (load) inertia

may be based on the data given in IEC 34-12, Table III, or may be calculated using the following

formula:

J = K x P0.9x p 2.5

where: J = Moment of inertia; mr2 (kg m2)

K = 0.04 for 50 Hz installations

0.03 for 60 Hz installations

P = Motor rated output power (kW)

p = number of pole pairs

When definite values of the load inertia and driven equipment torque-speed curves under operating

conditions are known, the exact running-up time shall be recalculated by the motor manufacturer.

The motor manufacturer shall liaise with the driven equipment manufacturer to obtain thenecessary data.


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5.5 ALLOWABLE RUNNING-UP TIME (ART)

The Manufacturer shall state in the quotation the allowable running-up time at 80% and 100%rated voltage applied at the motor terminals.


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5.6 STALLING TIME

If requested, the Manufacturer shall state in the quotation the maximum allowable stalling time

with rated voltage and frequency applied at the motor terminals.


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5.7 TEMPERATURE LIMITATIONS

The maximum allowable temperature rise of the electric motor is dependent on:

- the maximum coolant temperature;

- the maximum allowable temperature of the insulation materials used in the motor;

NOTE: Although the insulation materials used in the motor shall be at least Class F materials, the maximum continuous

operating temperature at full load and rated voltage and frequency applied shall be limited to the maximum

permissible temperature for Class B materials.

- the particular situation in which the motor is used, e.g. limiting temperatures in hazardous areas.


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5.8 CRITICAL SPEEDS

Motors shall have a rigid, undercritical rotor-bearing system with the first critical speed not lower

than 125% of the synchronous motor speed.

* However, motors with a rated output in excess of 200 kW may have a flexible, overcritical rotor-

bearing system. The first critical speed shall be lower than 80% of the synchronous motor speed.

The second critical speed shall not be lower than 125% of the synchronous motor speed.

At the first critical speed, the bearing vibration of the motor shall not exceed twice the values

specified in (5.9).

NOTE: Vibration reading at critical speed shall be taken with motor rigid mounted, uncoupled and free coasting from rated

speed to rest.

When the driven equipment manufacturer has to perform a torsional vibration analysis of thecomplete motor-driven train, the motor manufacturer shall provide the physical data required for

the torsional analysis. This will include dimensional data required to prepare the torsional model as

well as motor dynamic torque characteristics for both start-up and normal operation.

Resonance of the motor frame, resulting in vibrations exceeding those specified in (5.9), shall notoccur during start and normal operation. Motor frames shall not exhibit resonance frequencies

which can be excited by the supply frequency or its harmonics or by the rotational speed or its

harmonics.


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5.9 VIBRATIONS

5.9.1 General

Vibration tests shall be conducted according to the two conditions below which are specified in

detail in IEC 34-14:

- Free suspension

This condition is achieved by suspending the machine on a spring or by mounting on an elastic

support (springs, rubber, etc.).

- Rigid mounting

The machine shall be clamped directly, or through its base plate, to a solid floor.

5.9.2 Bearing vibration velocity

When freely suspended, the vibration of the motor shall not exceed 1.8 mm/s (rms).

When rigidly mounted, the vibration of the motor shall not exceed 2.8 mm/s (rms).

Maximum allowable vibration levels shall apply to all operating temperatures of the motorbetween ambient and maximum operating temperature and to all operating conditions between no-

load and full-load.

The measurements shall be taken in the direction of the three mutually perpendicular axes at the

bearings and mounting points of the motor. Details regarding the location of the measuring points

are given in IEC 34-14.

Criteria to evaluate the test and test results are provided in Appendix 2.

5.9.3 Two-pole cage-induction motors

Two-pole cage-induction motors, which will inherently demonstrate a higher contribution of twice

the supply frequency to the overall vibration, shall be subjected to a broad-band vibration analysis.

This requirement applies to motors with a rated output in excess of

110 kW.The contribution of twice the supply frequency, 100 Hz or 120 Hz, to the overall vibration shall

not exceed 1.4 mm/s (rms).

5.9.4 Shaft vibration amplitude measurements

If stated in the requisition, each bearing of a motor equipped with sleeve bearings shall beprovided with two non-contacting eddy current proximity probes in accordance with API 670. The

type and model number of the required proximity probes will be advised by the Principal. The

probes shall be located at 90 to each other and mounted in such a way that replacement is possible

whilst the motor is running. Rotors shall be checked for run-out and the correct location of the

probe elements shall be determined before installation in the machine housing.

For bearings fitted with proximity probes, the unfiltered double amplitude of shaft vibration (peak-

to-peak) including shaft run-out, relative to each radial bearing, with rated voltage and frequency

applied, and at any load condition between no-load and full load, shall not exceed the followingvalues:

- 50 m for two-pole motors;

- 60 m for four-pole motors;

- 75 m for six-pole or higher motors.

NOTE: Shaft run-out is the total indicator reading in a radial direction when the shaft is rotated in its bearings. The total

mechanical and electrical run-out combined shall not exceed 25% of the maximum allowable peak-to-peak vibration.

Electrical run-out can be determined by slowly rolling the rotor in bearings or vee-blocks while measuring run-out

with a proximity probe and a dial indicator at the proposed shaft location.


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5.9.5 Motor frame vibration velocity

The vibration severity of the motor frame, including main terminal boxes, shall not exceed 4.5

mm/s (rms).


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5.10 NOISE CONTROL

5.10.1 General

ISO 1680-2 shall apply, with the following conditions.

5.10.2 Noise limits

The sound pressure level of the loaded machine shall not exceed 85 dB(A) in the work area, i.e.

any position accessible to personnel not less than 1 metre from equipment surfaces.

For motors of 75 kW and lower power rating, the sound pressure level of the loaded machine shall

not exceed 82 dB(A) in the work area.

In the event that more stringent limits are required, this will be indicated in data/requisition sheetDEP 31.10.00.94-Gen., which will also form part of the requisition.

During tests in the motor factory where the motor cannot be reasonably fully loaded with the

driven equipment, an indication of satisfactory condition may be obtained if the sound pressure

level does not exceed the specified work area limit less 3 dB(A).

The mean sound level shall not be used as a criterion, unless specifically requested by the Principalfor meeting lower limits specified in the requisition.

If the motor produces noise with tonal components, the maximum sound pressure levels shall be 5

dB(A) less than the values stated above or in the requisition.

NOTE: A tonal component is considered to exist if the level of any one-third octave band exceeds the level of the adjacent

bands by 5 dB with the sound meter set to linear response.

5.10.3 Noise abatement

Motors shall meet the maximum allowable noise limits by design and not by corrective measures.

In situations where the Manufacturer intends to use corrective measures he shall state this in his

tender requisition and obtain approval from the Principal regarding the construction materials used

and safety aspects.

Where the use of internal soundproofing material is unavoidable, such liners shall be held rigidlyby retaining mesh.

The acoustic measures shall not obstruct routine inspection and maintenance activities such as

lubrication of bearings and inspection of oil levels. The maximum allowable temperature rise of

the motor windings and bearings shall not exceed the limits specified in this DEP.


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5.11 PULSATING STATOR CURRENT

Motors driving equipment which requires a variable torque during each revolution, e.g.

reciprocating compressors or pumps, shall have sufficient inertia to limit the variations in the

motor stator current to a value not exceeding:

- 40% of the full-load current for cage-induction motors, or

- 66% of the full-load current for synchronous motors.

The additional inertia necessary to comply with the current variation and speed irregularity

requirements, shall be added to the rotating mass of the motor.

* If this requirement cannot be met, approval shall be obtained from the Principal regarding an

alternative design.

NOTE: The basis for determining this variation shall be by oscillograph measurement and not by ammeter reading. A line

shall be drawn on the oscillogram through the consecutive peaks of the current wave. This line is the envelope of

the current wave. The variation is the difference between the maximum and minimum ordinates of this envelope.

This variation shall not exceed the stated percentage of the peak value of the rated full-load current of the motor

(1.41 times the rms-rated full-load current).

Generally this test will be part of a site acceptance test.


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5.12 EXCITATION SYSTEM

Unless otherwise specified, synchronous motors shall be designed for continuous operation at a

power factor of 0.9 leading at rated output and a voltage applied at the motor terminals between90% and 110% of the rated voltage.

The excitation system shall be equipped with an automatic power factor controller. This controller

shall maintain the set power factor within a margin of + 2.5% to - 2.5%.

If the motor loses synchronism with the supply voltage, the solid state protection system shall

protect the field windings against excessive over-voltage and the excitation shall be disconnected

immediately. Such protection shall operate in the event of undervoltage.

Asynchronous operation of the motor with the excitation voltage applied shall be avoided to the

largest possible extent.

The Manufacturer shall clarify the protection being offered in this respect. In any case, he shall

provide a stability curve identifying maximum allowable operating time versus remnant voltage

(see 6.14).


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Air-to-water heat exchangers shall be provided with provisions to drain the heat exchanger and to

release air trapped in the heat exchanger during filling.

The interior of air-to-water cooled motors shall be constructed so that water condensation leaking

from the cooler will collect and drain from the motor without dripping onto the windings.

For air-to-air cooled motors, with cooling methods IC6A1A1, IC6A1A6, a cooling air RTD

temperature detector shall be provided to measure the temperature of the internal cooling air after

the heat exchanger.

Air-to-water cooled motors shall be furnished with the following auxiliary devices:

- RTD element to measure the internal cooling air temperature after the heat exchanger.

- local indicating instrument to measure the internal cooling air temperature before and after the

heat exchanger.

- water leakage detector.


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6.2 ANTI-CONDENSATION HEATERS

Adequate provisions shall be made to avoid deterioration of the motor caused by condensation.

Anti-condensation heaters shall be provided for HV machines unless specifically excluded in therequisition.

Anti-condensation heaters shall be of a fully insulated design and suitable for 220-254 Volts singlephase supply, unless otherwise specified.

Anti-condensation heaters shall be arranged to provide uniform heating of the stator and, if

applicable, the rotor windings and shall maintain the temperature of the motor windings

approximately 5 C above ambient temperature.

The surface temperature of the heater element or of the motor enclosure shall not exceed the

limiting temperature specified.

The connecting leads of the heater elements shall be brought out to terminals in a separate heater

terminal box mounted on the motor frame. A prominent warning label shall be provided, with the

words:

"Warning - Circuit may be live"


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6.3 WINDINGS

6.3.1 General

The following requirements apply to all machine windings including those of synchronous machine

exciters.

The complete insulation system of both LV and HV motors, including all insulation materials, shall

meet the requirements for class F insulation.

All insulation materials used for both stator and, if applicable, rotor and exciter windings shall be

at least class F materials in accordance with IEC 85.

* The Manufacturer shall demonstrate that adequate precautions are taken to prevent the formation

of voids in the insulation during curing. In the absence of such demonstration, the machines shall

be continuously rolled during curing.

6.3.2 LV motors

Stator windings of LV motors shall be made of enameled wire with suitable earth and interphase

insulation. Wire enamels with a thermal endurance life of less than

200 000 hours at 120 degrees Celsius, e.g. epoxy based enamels, shall not be used.

* After installation of the windings and connection of the coils, the windings shall be fully

impregnated to restrict the movement of the coils and to allow adequate heat dissipation. Coating

or painting is not recognised as impregnation.

Curing of the insulation material shall be performed at the temperature specified by the

Manufacturer.

6.3.3 HV motors

All HV motors shall have their stator windings star-connected.

Stator windings of HV motors shall be preformed and shall be made of rectangular copper

conductors adequately covered with glass silk material or other insulation materials of similar

dielectric strength and ageing properties.

All stator windings of HV motors shall have identical insulation levels irrespective of the electrical

location of the winding, e.g. starpoint side or HV side.

The main insulation material used for machines with a rated voltage in excess of 5 kV shall be

mica.

The windings of motors with rated voltage in excess of 5 kV shall have anti-corona protection by

means of semi-conducting tape covering the slot part of the winding. Anti-corona protection by

means of semi-conducting paint is not permitted.

The windings of motors with rated voltage in excess of 7 kV shall, in addition to anti-corona

protection, have stress grading.

* Regarding the final insulation of the stator windings three insulation methods are recognised:

1. full vacuum pressure impregnation (VPI) method.

2. individual forming and curing of the slot parts of the windings with subsequent impregnation

of the complete stator according to the VPI method.

3. the resin rich method with individual forming and curing of the slot parts of the windings and

with subsequent impregnation or spraying (non-vacuum) of the stator endwindings. The

insulation of the endwindings is achieved by means of resin loaded tape.

All three insulation methods can be accepted if properly administered by the Manufacturer.

However, the first and second method described are preferred.

The Manufacturer shall indicate in the quotation the insulation method applied.


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For the third method described, the impregnation or spraying and subsequent curing process shall

be applied at least twice, and shall be completed by a protective coating to give additional

protection against salt and abrasive materials.

Prior to impregnation the complete stator shall be dried and heated up to the temperature specifiedby the Manufacturer.

After impregnation, curing of the insulation material shall take place in an oven.

All windings shall be adequately supported, braced and blocked to provide sufficient rigidity and

to limit endwinding vibration and subsequent cracking of the winding insulation.

Windings shall be able to withstand the dynamic forces which result from frequent starting, and

restarting against full opposite residual voltage.

Inter-coil packing blocks shall be positively secured to the coils by binding with cord or tape. It is

not sufficient to rely on varnish to hold the blocks in place or to rely on tight initial wedging.

Stator coils shall be tightly fitted in the slots with a pre-impregnation air gap between winding and

slot wall of not more than 0.15 mm. The wedging method shall cater for thermal cycling and

vibration over the specified 20 years.

6.3.4 Voltage withstand level

HV motors shall withstand impulse voltage levels to IEC 34-15 for main insulation and inter-turn

insulation. For inter-turn insulation, only wavefronts of 0.3 s or less shall be applied (seeAppendix 1).

6.3.5 Polarisation index

The polarisation index of HV stator windings shall have a value of at least 2 unless the insulation

value of the motor exceeds a value of 120 x (Un + 1) Megohm, in which case the polarisation

index shall be at least 1.5.

NOTE: Un= rated line-line voltage expressed in kV.

6.3.6 Slot wedges

Magnetic slot wedges are acceptable provided the Manufacturer:

- demonstrates at least 5 years of satisfactory running on past installations;

AND

- guarantees against failure of wedges for at

Documents

FPSO_Electric Motors Specification.pdf