Motores Yaskawa

7/30/2019 Motores Yaskawa

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11/28/2012

Yaskawa Electric

America

Motor Basics

Version 3.00


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Three Phase Motor Construction

Stator

Rotor

Windings - Electromagnets Rotor bars


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End View

Rotor

Stator

Enclosure

Air Gap

Stator Windings

Shaft


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End View

T1

T2

T2

T3

T1

T3


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Motor Operation


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Motor Operation


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Motor Operation


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Motor Operation


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Three Phase Motor ConstructionT1

End View

T2

T2

T3

T1

T3

+

+

+

+ denotes current is moving away from you

denotes current

is moving towards you


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Rotation of the motor

+

+

+S

N

T1T3 T2

One Cycle*

* - current waveform


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+

+

+

T1T3 T2

One Cycle*


+

+

+S

N


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+

+

+

T1T3 T2

One Cycle*


+

+

+S

N

+

+

+


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+

+

+ S

N

T1T3 T2

One Cycle*


+

+

+S

N

+

+

+

+

+

+


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+

+

+

N

T1T3 T2

One Cycle*


+

+

+S

N

+

+

+

+

+

+

+

+

+ S

N


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+

+

+

N

T1T3 T2

One Cycle*


+

+

+S

N

+

+

+

+

+

+

+

+

+ S

N

+

+

+

N


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+

+

+S

N

T1T3 T2

One Cycle*


+

+

+S

N

+

+

+

+

+

+

+

+

+ S

N

+

+

+

N

+

+

+

N


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Calculating SynchronousSpeed of the Motor

P

f N o120


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Poles & Synchronous RPM @ 60Hz

Magnetic Poles Synchronous RPM2 3600

4 1800

6 1200

8 900

7200 = Synchronous RPM P

7200 = P

Synchronous RPM


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T1

End View

T2

T2

T3

T1

T3


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T1

End View

T2

T2

T3

T1

T3


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End View

Magnetic Poles

T1a

T2a

T2a

T1a T1b

T2b

T2b

T3b

T1b

T3b

T3b

T3b


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What is Slip ?To produce torque in an induction motor, current

must flow in the rotor.

To induce current flow in the rotor, the rotor speed must be slightly slower than the

synchronous speed.The difference between the synchronous speed

and the rotor speed (rated speed) is called the slip.

Stator

Flux

Rotor Slip


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Calculating Motor Rated Speed Formula to find actual motor RPM

N =120 f

P( 1 - s )

Where:

N - RPM of the motor

f - Frequency in Hz

P - Number of poles of the motor

s - (N o - N) / N o


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Speed - Torque Curve(600%)

Locked Rotor Torque (150%)

Full Load

Torque (100%)

Pull Up Torque (125%)

Breakdown Torque (200-250%)

Rated Speed Synch Speed SPEED

TORQUE CURRENT

No Load Current (30%)

Slip

(300%)

(300%)

(200%)


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Speed - Torque Curve

SPEED

TORQUE


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Typical NEMA Design Characteristics

0

100%

SPEED

T O R Q U E 200%

300%

100%

NEMA Design A

High breakdown torque

Normal starting torque

High starting current

Low full load slip

Used in applications that require:

Occasional overloads

Better efficiency


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0

100%

SPEED

T O R Q U E 200%

300%

100%

Design B

NEMA Design B

Normal breakdown torque

Normal starting torque

Low starting current

Normal full load slip

less than 5%

General Purpose Motor

Design A


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0

100%

SPEED

T O R Q U E 200%

300%

100%

Design C NEMA Design C

Low breakdown torque

High starting torque

Low starting current

Normal full load slip

less than 5%


high breakaway torque

Design A

Design B


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0

100%

SPEED

T O R Q U E 200%

300%

100%

Design D NEMA Design D

High breakdown torque

High starting torque

Normal starting current

High full load slip

5 - 13%


high breakaway torque

Design C

Design A

Design B


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Motor Nameplate Data


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Understanding the NameplateHP- Horsepower

The horsepower figure stamped on

the nameplate is the horsepower the motor is rated to develop when connected to a circuit of the voltage,frequency and number of phases specified on the

motor nameplate.


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Rotational Horsepower Formula

The horsepower formula in simplified form

HP =Torque x RPM

5250

Where:

Torque - Amount of torque in lb.ft.RPM - RPM of the motor

5250 - constant obtained by dividing 33,000

by 6.28

HP x 5250

RPMTorque =OR


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Understanding the Nameplate

RPM - Revolutions per Minute

The RPM value represents the approximate speed at which the motor will run when properly connected and delivering its rated output


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Poles Synchronous RPM Typical Nameplate RPM2 3600 3450

4 1800 1725

6 1200 1140

8 900 850


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Voltage

The rated voltage

figure on the motor nameplate refers to the voltage of the supply circuit to which the motor should be connected,to produce rated horsepower and RPM.

Key piece of information when selecting an inverter.


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Effects of Voltage Variationon the Motor at 60Hz

Low Voltage

Higher than normal current

Higher than normal motor temperature

High Voltage

Higher than normal current

Lower than normal power

factor


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Phase

The phase figure on

the motor nameplate describes the alternating current system that the motor has been designed for.



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Hz-Frequency

The frequency figure

on the motor nameplate describes the alternating current system frequency that must be applied to the motor to achieve rated speed and horsepower.


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Amps

The amp figure on

the motor nameplate represents the approximate current draw by the motor when developing rated horsepower on a circuit of the voltage and frequency specified

on the nameplate.



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NEMA Design

The NEMA Design

rating specifies the speed torque curve that will be produced by the motor.


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Insulation Class

The insulation class

letter designates the amount of allowable temperature rise based on the insulation system and the motor service factor.


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Insulation Class InformationMost common insulation classes are class B and F

Insulation Class Ambient Temp. Temp. Rise Total Temp. A 40 o C 65 o C 105 o C

B 40 o C 90 o C 130 o C

F 40 o C 115 o C 155 o C

H 40 o C 140 o C 180 o C


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Understanding the NameplateS.F. - Service Factor

The number by which the horsepower rating is

multiplied to determine the maximum safe load that a motor may be expected to carry continuously

Example - a 10HP motor with a service factor of 1.15 will deliver 11.5 horsepower continuously without exceeding the allowable temperature rise

of its insulation class


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Frame

The frame designation refers to the physical size of the motor as well as certain construction features such as the shaft and mounting dimensions.


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Types of Motor Enclosures

Open Drip-proof (ODP)

Totally enclosed non-ventilated (TENV)Totally enclosed fan cooled (TEFC)Totally enclosed blower cooled (TEBC)


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ODP Open drip-proof Ventilating openings permit passage of external cooling air over and around the windings of the motor.

Small degree of protection against liquid or solid particles entering the enclosure.


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TENV Totally enclosed

non-ventilated Totally enclosed enclosure with no means of external cooling.


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TEFC Totally enclosed fan-cooled Totally enclosed enclosure with external cooling

means, such as a shaft connected fan


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TEBC Totally enclosed blower-cooled

Totally enclosed enclosure with external cooling

means such as a separately controlled motor/blower


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TEFC Speed Ranges

Constant Torque 4:1 (15-60 Hz)

Constant Torque 10:1 (6-60 Hz)

Variable Torque 1-60 Hz 2:1 (30-60 Hz) CT


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TENV/TEBC Speed Ranges

Constant Torque 0 to Base Speed 100:1 (0.6-60 Hz)1000:1 (0.06-60 Hz)


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Motor Retrofit Summary

RPM

Volts Phase Amps NEMA Design Frame + any prefix or suffix letter codes

Location

Mounting Orientation Application Enclosure Style Motor Control Method

Inverter-Duty?


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Motor Basics ExerciseAnswer the following questions using your knowledge and/or the documents from this class.

1.) Write down the formula to calculate synchronous motor speed (please use the simplified form).

2.) To calculate the actual motor speed what has to be included in the above formula ?

3.) The majority of electric motors used in general purpose applications in industry today are what NEMA design ?

4.) A NEMA design D motor is characterized by very high breakdown torque,and a large percentage of slip ? (True or False)

5.) Name the two pieces of information needed off the motor nameplate when selecting an inverter.


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Motor Basics ExerciseAnswer the following questions using your knowledge and/or the documents from this class.

1.) Write down the formula to calculate synchronous motor speed (please use the simplified form).

Voltage and Full Load Amps (FLA)

120 x f / P

slip (120 x f / P) - slip

NEMA design B

True

2.) To calculate the actual motor speed what has to be included in the above formula?

3.) The majority of electric motors used in general purpose applications in industry today are what NEMA design?

4.) A NEMA design D motor is characterized by very high breakdown torque,and a large percentage of slip ? (True or False)

5.) Name two key pieces of information needed off the motor nameplate when selecting an inverter.


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11/28/2012

Yaskawa Electric America Technical Training Services

09/06/2001


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Yaskawa Electric America Technical Training Services

For training information, please:

Call us at 1-800-YASKAWA and select option #6

Check out our website at www.yaskawa.com

E-mail us at [email protected]
http://www.yaskawa.com/http://www.yaskawa.com/

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Motores Yaskawa