Principles of Management

Naresh Kumar Goel

HOD Electrical,

Govt. Polytechnic,

Ambala City

Learning Objectives

Define Managers And Management.

Explain What Managers Do.

Describe The Competencies Used In Managerial Work And Assess Your Current Competency Levels.

Introductory Concepts: What Are

Managerial Competencies?

Competency – a combination of knowledge,

skills, behaviors, and attitudes that contribute to

personal effectiveness

Managerial Competencies – sets of knowledge,

skill, behaviors, and attitudes that a person

needs to be effective in a wide range of positions

and various types of organizations

Why are Managerial Competencies

Important?

You need to use your strengths to do your best

You need to know your weaknesses

You need developmental experiences at work to become

successful leaders and address your weakness

You probably like to be challenged with new learning

opportunities

Organizations do not want to waste human resources

Globalization deregulation, restructuring, and new

competitors add to the complexity of running a business

A Model of Managerial Competencies

Teamwork

Competency

Global

Awareness

Competency

Strategic

Action

Competency

Planning and

Administration

Competency

Self-Management

Competency

Communication

Competency

A Model of Managerial Competencies

Teamwork

Competency

Global

Awareness

Competency

Strategic

Action

Competency

Planning and

Administration

Competency

Self-Management

Competency

Communication

Competency

Managerial

Effectiveness

What Is An Organization?

A formal and coordinated group of people who

function to achieve particular goals

These goals cannot be achieved by individuals

acting alone

Characteristics of an

Organization

An organization has a structure.

An organization consists of a group of people striving to reach goals that individuals acting alone could not achieve.

Management

Organization

Two or more people who work together in a structured

way to achieve a specific goal or set of goals.

Goals

Purpose that an organization strives to achieve;

organizations often have more than one goals, goals are

fundamental elements of organization.

The Role of Management

To guide the organizations towards goal

accomplishment

- People responsible for

directing the efforts aimed

at helping organizations

achieve their goals.

- A person who plans,

organizes, directs and

controls the allocation of

human, material, financial,

and information resources

in pursuit of the

organization’s goals.

Management

Management refers to the tasks and activities

involved in directing an organization or one of

its units: planning, organizing, leading, and

controlling.

The process of reaching organizational goals by

working with and through people and other

organizational resources.

Functional Managers: A manager responsible for

just one organizational activity such as accounting,

human resources, sales, finance, marketing, or

production

Focus on technical areas of expertise

Use communication, planning and

administration, teamwork and self-

management competencies to get work

done

Function: A classification referring to a group of

similar activities in an organization like marketing or operations.

Basic Managerial Functions

Organizing

Planning

Controlling

Leading

Management and Organizational Resources

Planning involves tasks that must be

performed to attain organizational goals,

outlining how the tasks must be performed, and

indicating when they should be performed.

Planning

Determining organizational goals and

means to reach them

Managers plan for three reasons

1. Establish an overall direction for the

organization’s future

2. Identify and commit resources to achieving goals

3. Decide which tasks must be done to reach those

goals

Organizing means assigning the planned tasks to

various individuals or groups within the

organization and cresting a mechanism to put plans

into action.

Organizing

Process of deciding where decisions will be made, who

will perform what jobs and tasks, and who will report

to whom in the company

Includes creating departments and job descriptions

Leading (Influencing) means guiding the activities

of the organization members in appropriate

directions. Objective is to improve productivity.

Leading

Getting others to perform the necessary tasks by

motivating them to achieve the organization’s goals

Crucial element in all functions

1. Gather information that measures recent performance

2. Compare present performance to pre-established standards

3. Determine modifications to meet pre-established standards

Controlling

Process by which a person, group, or

organization consciously monitors performance

and takes corrective

action

Top Managers

Responsible for providing the overall direction of an

organization

Develop goals and strategies for entire organization

Spend most of their time planning and leading

Communicate with key stakeholders—stockholders,

unions, governmental agencies, etc., company

policies

Use of multicultural and strategic action

competencies to lead firm is crucial

Levels of Management

First-line Managers: have direct responsibility for

producing goods or services Foreman, supervisors,

clerical supervisors

Middle Managers:

Coordinate employee activities

Determine which goods or services to provide

Decide how to market goods or services to customers

Assistant Manager, Manager (Section Head)

Top Managers: provide the overall direction of an

organization Chief Executive Officer, President, Vice

President

First-line Managers

Directly responsible for production of goods or services

Employees who report to first-line managers do the

organization’s work

Spend little time with top managers in large organizations

Technical expertise is important

Rely on planning and administration, self-management,

teamwork, and communication competencies to get work

done

Middle Managers

Responsible for setting objectives that are consistent with

top management’s goals and translating them into specific goals and plans for first-line managers to implement

Responsible for coordinating activities of first-line

managers

Establish target dates for products/services to be delivered

Need to coordinate with others for resources

Ability to develop others is important

Rely on communication, teamwork, and planning and

administration competencies to achieve goals

Introductory Concepts: What Are

Managerial Competencies?

Competency – a combination of knowledge,

skills, behaviors, and attitudes that contribute to

personal effectiveness

Managerial Competencies – sets of knowledge,

skill, behaviors, and attitudes that a person

needs to be effective in a wide range of positions

and various types of organizations

Six Core Managerial Competencies:

What It Takes to Be a Great Manager

Communication Competency

Planning and Administration Competency

Teamwork Competency

Strategic Action Competency

Multicultural Competency

Self-Management Competency

Communication Competency

Ability to effectively transfer and exchange information

that leads to understanding between yourself and others

Informal Communication

Used to build social networks and good

interpersonal relations

Formal Communication

Used to announce major events/decisions/

activities and keep individuals up to date

Negotiation

Used to settle disputes, obtain resources,

and exercise influence

Deciding what tasks need to be done, determining

how they can be done, allocating resources to enable

them to be done, and then monitoring progress to

ensure that they are done

Information gathering, analysis, and problem solving

from employees and customers

Planning and organizing projects with agreed

upon completion dates

Time management

Budgeting and financial management

Accomplishing tasks through small groups of

people who are collectively responsible and

whose job requires coordination

Designing teams properly involves having

people participate in setting goals

Creating a supportive team environment gets

people committed to the team’s goals

Managing team dynamics involves settling

conflicts, sharing team success, and assign tasks

that use team members’ strengths

Strategic Action Competency

Understanding the overall mission and values of

the organization and ensuring that employees’ actions match with them

Understanding how departments or divisions of

the organization are interrelated

Taking key strategic actions to position the firm

for success, especially in relation to concern of

stakeholders

Leapfrogging competitors

Understanding, appreciating and responding to

diverse political, cultural, and economic issues

across and within nations

Cultural knowledge and understanding of the

events in at least a few other cultures

Cultural openness and sensitivity to how others

think, act, and feel

Respectful of social etiquette variations

Accepting of language differences

Multicultural Competency

Self-Management Competency

Developing yourself and taking responsibility

Integrity and ethical conduct

Personal drive and resilience

Balancing work and life issues

Self-awareness and personal development

activities

CIRCUIT BREAKER

WHAT IS A CIRCUIT BREAKER?

• A circuit breaker is an equipment that breaks a

circuit either manually or automatically under

all conditions at no load, full load or short

circuit.

Operating Principle

Two contacts called electrode remains closed under normal operating conditions. When fault occurs on any part of the system, the trip coil of the circuit breaker get energized and contacts are separated.

Arc Phenomenon

• An arc is struck when contacts are separated. The

current is thus able to continue. Thus the main

duty of a circuit breaker is to distinguish the arc

within the shortest possible time.

• The arc provides the low resistance path to the

current and the current in the circuit remains

uninterrupted.

The arc resistance depends upon the following factors. Degree of ionization Length of the arc Cross Section of the arc

Methods of Arc Extinction

High Resistance Method Low Resistance Method

TYPES OF

CIRCUIT

BREAKER

OIL

CIRCUIT

BREAKER

AIR BLAST

CIRCUIT

BREAKER

SF6

CIRCUIT

BREAKER

VACCUM

CIRCUIT

BREAKER

Breaker Used In 132KV Grid

Station

• Oil Circuit Breaker

• Vacuum Circuit breaker

• SF6 Circuit Breaker

Air

cushion

Bulk Oil Circuit breaker

Low Oil Circuit Breaker

Consists of two parts.

Supporting

Chamber.

Circuit-Breaking

chamber( consist

of fixed and

moving contact)

Disadvantages Of Oil Circuit Breaker

• It is inflammable and there is a risk of fire.

• It may form an explosive mixture with air.

• It requires maintenance.

• Absorbs moisture, so dielectric strength reduces.

• Oil leakage problem.

• Oil has to be replaced after some operations because of the carbonization of oil.

Vacuum Circuit Breaker

• Vacuum is used as an arc quenching medium.

• Have greatest insulating strength.

• 10-7 to 10-5 pressure is to be maintained.

• Used in 11KV panel in control room of grid

station.

Vacuum Circuit Breaker

Advantages

• Compact, reliable and have longer life.

• No fire hazards.

• No generation of gas during and after

operation.

• Can interrupt any fault current.

• No noise is produced while operating.

• Require less power for control operation.

SF6 Circuit Breaker

1. Sulphur Hexafluoride (SF6) gas is used as an arc quenching medium.

2. SF6 is an electro-negative gas.

3. It has strong tendency to absorb electrons.

4. When contact are opened in a high pressure flow of SF6 gas, arc produced.

5. Free electron in the arc are captured by the gas.

6. Which build up enough insulation strength to extinguish arc.

7. it is much effective for high power and high voltages services,

Advantages

• Simple construction, less cost.

• SF6 gas is non flammable, non toxic & chemical inert gas.

• Same gas is recirculated in the circuit.

• Maintenance free C.B.

• Ability to interrupt low and high fault current.

• Excellent Arc extinction.

Advantages Of SF6 Over Oil Circuit Breakers

• Short arcing time

• Can interrupt much larger currents

• Gives noiseless operation due to its closed gas circuit

• No moisture problem

• No risk of fire

• No carbon deposits. So no tracking and insulation

problems

• Low maintenance cost

Transformer

An A.C. device used to change high voltage low

current A.C. into low voltage high current A.C. and

vice-versa without changing the frequency

In brief,

1. Transfers electric power from one circuit to another

2. It does so without a change of frequency

3. It accomplishes this by electromagnetic induction

4. Where the two electric circuits are in mutual

inductive influence of each other.

Principle of operation

It is based on principle of MUTUAL

INDUCTION. According to which an e.m.f. is

induced in a coil when current in the

neighbouring coil changes.

Constructional detail : Shell type

• Windings are wrapped around the center leg of a

laminated core.

Core type

• Windings are wrapped around two sides of a laminated square

core.

Sectional view of transformers

Note:

High voltage conductors are smaller cross section conductors

than the low voltage coils

Construction of transformer from

stampings

Core type

Fig1: Coil and laminations of

core type transformer Fig2: Various types of cores

Shell type

• The HV and LV windings are split into no. of sections

• Where HV winding lies between two LV windings

• In sandwich coils leakage can be controlled

Fig: Sandwich windings

Transformer with conservator and

breather

Working of a transformer

1. When current in the primary coil

changes being alternating in

nature, a changing magnetic field

is produced

2. This changing magnetic field gets

associated with the secondary

through the soft iron core

3. Hence magnetic flux linked with

the secondary coil changes.

4. Which induces e.m.f. in the

secondary.

Ideal Transformers

• Zero leakage flux:

-Fluxes produced by the primary and secondary currents

are confined within the core

• The windings have no resistance:

- Induced voltages equal applied voltages

• The core has infinite permeability

- Reluctance of the core is zero

- Negligible current is required to establish magnetic

flux

• Loss-less magnetic core

- No hysteresis or eddy currents

Ideal transformer

V1 – supply voltage ; I1- noload input current ;

V2- output voltgae; I2- output current

Im- magnetising current;

E1-self induced emf ; E2- mutually induced emf

Phasor diagram: Transformer on No-

load

Transformer on load assuming no

voltage drop in the winding

Fig shows the Phasor diagram of a transformer

on load by assuming

1. No voltage drop in the winding

2. Equal no. of primary and secondary turns

Transformer on load

Fig. a: Ideal transformer on load

Fig. b: Main flux and leakage

flux in a transformer

Phasor diagram of transformer with

UPF load

Phasor diagram of transformer with

lagging p.f load

Phasor diagram of transformer with

leading p.f load

Equivalent circuit of a transformer

No load equivalent circuit:

Equivalent circuit parameters referred to

primary and secondary sides respectively

Transferring secondary parameters to

primary side

Transformer Tests

Electrical Machines

•The performance of a transformer can be calculated on the basis of

equivalent circuit

•The four main parameters of equivalent circuit are:

- R01 as referred to primary (or secondary R02)

- the equivalent leakage reactance X01 as referred to primary

(or secondary X02)

- Magnetising susceptance B0 ( or reactance X0)

- core loss conductance G0 (or resistance R0)

•The above constants can be easily determined by two tests

- Oper circuit test (O.C test / No load test)

- Short circuit test (S.C test/Impedance test)

•These tests are economical and convenient

- these tests furnish the result without actually loading the

transformer

In Open Circuit Test the tra sfor er’s secondary winding is open-circuited, and

its primary winding is connected to a full-rated line voltage.

• Usually conducted on

H.V side

• To find

(i) No load loss or core

loss

(ii) No load current Io

which is helpful in

finding Go(or Ro ) and Bo

(or Xo )

2

0

2

00

2

0

oc00

2

0oc

0

0o000

22

000m

00wc

00

0

000

B esusceptanc Exciting &

V

WG econductanc Exciting ;GV W

Y ;YVI

sinI I

cosI I

cos

cosloss Core

GY

V

I

-IIIor

Ior

IV

W

IVW

w

oc

oc

Open-circuit Test

0

0

0

0

0

0

0

0

V

IB

V

IG

I

VX

I

VR

w

w

Short-circuit Test In Short Circuit Test the secondary terminals are short circuited, and the

primary terminals are connected to a fairly low-voltage source

The input voltage is adjusted until the current in the short circuited windings

is equal to its rated value. The input voltage, current and power is

measured.

• Usually conducted on L.V side

• To find

(i) Full load copper loss – to pre determine the efficiency

(ii) Z01 or Z02; X01 or X02; R01 or R02 - to predetermine the voltage

regulation

2

01

2

0101

01

2

sc01

01

2

sc

X

WR

W losscu load Full

RZ

I

VZ

I

RI

sc

sc

sc

sc

Formula: voltage regulation

leadingfor '-' and laggingfor ''

V

sincos

V

Vregulation %

luesprimary va of In terms

leadingfor '-' and laggingfor ''

V

sincos

V

Vregulation %

valuessecondary of In terms

1

10111011

1

'

21

20

20222022

20

220

where

XIRIV

where

XIRIV

Transformer Efficiency

Transformer efficiency is defined as (applies to motors, generators and

transformers):

%100in

out

P

P

%100

lossout

out

PP

P

Types of losses incurred in a transformer:

Copper I2R losses

Hysteresis losses

Eddy current losses

Therefore, for a transformer, efficiency may be calculated using the following:

%100cos

cosx

IVPP

IV

SScoreCu

SS

Losses in a transformer

Core or Iron loss:

Copper loss:

All day efficiency

hours) 24 (kWhin Input

kWhin output

in wattsinput

in wattsput out efficiency commercialordinary

day forall

•All day efficiency is always less than the commercial efficiency

1

Introduction to Energy

Solar Energy

2

The different forms of energy:

Energy can be obtained in number of way. It may be in

the form of

(1) Chemical energy - due to chemical reaction

(2) Electrical energy - due to flow of electron

(3) Heat energy - due to thermal vibration

(4) Light energy - due to radiation of light

(5) Mechanical energy – due to moving parts

(6) Nuclear energy - due to nuclear reaction

The SI unit of energy is Joule (or) N/m.

Definition of Energy: Energy can be defined as the ability

(or) capacity to do work

3

Law of conservation of energy

According to law of conservation of energy, Energy can

neither be created nor destroyed. But, one form of energy

can be converted to another form.

Example: A battery generates electrons from chemical

reactions, which are used to make electrical energy.

A heater convert electrical energy into heat energy.

The human leg converts the chemical energy stored in the

muscles into mechanical energy when you pedal a

bicycle.

4

Category of energy resource

On the basis of availability, the energy resources are

broadly categories as,

• Primary energy resources

• Secondary energy resources

Primary energy: All energy originates from natural sources

such as coal, solar, wind, hydro are called

primary energy resources.

Secondary energy: The energy converted from primary energy

sources. For example, the solar energy

can be converted into electricity

5

Types of Energy sources 1. Conventional energy sources (or) Non-renewable energy sources

2. Non-Conventional energy sources (or) Renewable energy sources

• Generally, non-renewable energy sources come out of the

ground as liquids, gases and solids.

Examples: The conventional (or) Non-renewable energy

sources are Oil, Coal, Petroleum and natural

gas, Nuclear energy

(1) Conventional energy (or) Non-renewable energy

Conventional (or) Non-renewable energy sources are those,

which cannot be replaced continuously.

6

We can obtain renewable energy from the sun, from the

water, from the wind, from crop residues and waste

The types of Non-conventional (or) Renewable energies are

Solar energy Tidal energy

Wind energy Hydro energy

Biomass energy Biofuels

Geothermal Wave Power

Non-Conventional energy (or) Renewable energy

Renewable energy is a source of energy that can never be

exhausted and can be replaced continuously

7

Solar energy

Solar energy comes from the light of the sun, which means it

is a renewable source of energy. We can use the sun light to

create pollution free electricity

The solar cell is the system used to convert the sunlight

energy into electrical energy

8

Solar collectors

9

Areas of the world with high Solar radiation

• The basic resource for all solar energy systems is the

sun.

• Knowledge of the quantity and quality of solar energy

available at a specific location is of prime importance

for the design of any solar energy system

10

• Although the solar radiation is relatively constant outside

the earth's atmosphere, local climate influences can

cause wide variations in available radiation on the

earth’s surface from site to site.

• In addition, the relative motion of the sun with respect to

the earth will allow surfaces with different orientations to

intercept different amounts of solar energy.

• It is the primary task of the solar energy system designer

to determine the amount, quality and timing of the solar

energy available at the site selected for installing a solar

energy conversion system.

1

LVDT

• You’re expected to learn

– Linear Variable Differential Transformer

(LVDT)

• Architecture

• Diagram

• Application

2

LVDT-Inductive T

A reliable and accurate sensing

device that converts linear position

or motion to a proportional

electrical output.

3

LVDT

The cross sectional view of

the DC LVDT at left shows the

built-in signal conditioning

electronics module. The

module is secured with a

potting compound that is not

shown in this drawing

4

Applications of LVDTs

5

Among the advantages of LVDT are as follows:

• It produces a higher output voltages for small

changes in core position.

• Low cost

• Solid and robust -capable of working in a wide

variety of environments.

• No permanent damage to the LVDT if

measurements exceed the designed range.

LVDT

6

LVDT

An inductor is basically a coil of wire

over a “core” (usually ferrous)

It responds to electric or magnetic

fields

A transformer is made of at

least two coils wound over the

core: one is primary and

another is secondary

Primary Secondary

Inductors and tranformers work only for ac signals

A

B

A

B

BAoutVVV

7

EXAMPLES OF LVDT APPLICATION

8

LVDT Operation

Windings are connected “series opposing” polarities of V1 and V2

oppose each other if we trace through

the circuit from terminal A to B.

If the core at the center, V1=V2, Vo=0

When the core is away from center

toward S1, V1 is greater than V2 and

the output voltage Vo will have the

polarity V1.

When the core is away from center

toward S2, V2 is greater than V1 and

the output voltage Vo will have the

polarity V2.

9

LVDT Operation

That is, the output ac voltage inverts

as the core passes the center position

The farther the core moves from

center, the greater the difference in

value between V1 and V2,

consequently the greater the value of

Vo.

Thus, the amplitude of Vo is a function

of the distance the core has moved,

and the polarity or phase indicates

which direction is has moved.

If the core is attached to a moving

object, the LVDT output voltage can be

a measure of the position of the

object.

10

LVDT Operation

11

Example

An ac LVDT has the following data; input 6.3V,

output 5.2V, range ±0.50 cm. Determine:

a) Plot of output voltage versus core position for a

core movement going from +0.45cm to -0.03cm?

b) The output voltage when the core is -0.35cm from

the center?

c) The core movement from center when the output

voltage is -3V?

d) The plot of core position versus output voltages

varying from +4V to -2.5V.

12

Student’s activity for next class

• Based on each measurement, I expect you to gather all the information in the following order – Type sensors

– Architecture

– Operation

– Application

– Diagram

• You will need to prepare study materials/notes based on the information above

• I will collect them by the end of next class (soft copy)

PLC’s Are ... • Similar to a Microcontroller:

– Microprocessor Based

– Onboard Memory for Storing Programs

– Special Programming Language: Ladder Logic

– Input/Output Ports

PLC’s Are...

• Dissimilar to Microcontrollers:

– Intended for Industrial Applications

– I/O Designed to interface with Control Relays

– Emphasis on Maximum Reliability

PLC’s

• Widely Applied in Every Industry

• Were Developed to Simplify the

Implementation of Control Automation

Systems in Plants and Assembly Lines

• Designed to Minimize the Number of

Control Relays in a Process and Maximize

the Ways Relays can be Used

• First Applied to Automobile Industry in the

Late 1960’s

• Flexible, Reliable and Low Cost

PLC Components

I/O Modules

• Input Modules: Input Signals can be AC or

DC, Analog or Digital

• Output Modules: Outputs are either AC or

DC Analog Signals (Although it is possible

to ‘Construct’ Digital Outputs) • Modern PLC’s have Expansion Ports to

Increase the Number of Available Inputs

and Outputs

Examples of I/O Signals

• Inputs:

– Pushbutton (Energizing or Grounding an Input)

– Relay Contact Output

– DC Voltage Level

– Digital Logic Signal (+5V or 0 V, etc)

• Outputs:

– 24 V ac

– 120 V ac

– 120 Vdc

– etcetera

PLC’s Use Ladder Logic

• Ladder Logic Diagrams Provide a Method

to Symbolically Show How Relay Control

Schemes are Implemented

• Relay Contacts and Coils, Inputs and

Outputs lie on “Rungs” Between the Positive and Ground Rails

Example of Ladder Diagram

Relays

• In General, Relays Transform a Control

Signal into a Control Action

• Relays Provide:

– Isolation Between Input and Output

– Leverage (Small Signal Can Control Large

Action)

– Automation (Minimize Human Interaction with

a Control Process)

Relay Applications

• Relays can be Designed to Perform Many

Functions

– Detect Out of Limit Conditions on Voltages

and Currents

– Start Motors

– Prevent Motors from Over Heating

– Control Assembly Lines

– Adjust Lighting

PLC Timers and Motor

Protection

Industrial Communications

• RS-422 (EIA 422): Asynchronous Serial

Communications , similar in many respects

to RS-232

• Faster (up to 100 Kbps) than RS-232

• Better Noise Immunity

– Differential (Balanced signal) Protocol

– Makes use of Twisted Pair lines - 1 pair for

transmit, one pair for receive (4 Lines vs. 3)

EIA-422 Basics

• Can be 1 Master Transmitter feeding up to

10 Slave Receivers

• Can be Peer-to-Peer, like RS-232

• Data is sent and received via Differential

Ports - Common Mode Rejection (Noise

common to both inputs is attenuated)

• Twisted Pair also reduces EMI at low cost

EIA 485 (RS-485) • More Modern, Faster and Flexible (supports TCP/IP)

• Since it uses a differential balanced line over twisted

pair (like EIA-422), it can span relatively large

distances (up to 4000 feet or just over 1200 metres).

• In contrast to EIA-422, which has a single driver

circuit which cannot be switched off, EIA-485 drives

need to be put in transmit mode explicitly by

asserting a signal to the driver. This allows EIA-485

to implement linear topologies using only two lines.

IEEE 802.3 (Ethernet)

• Star Topology (Hub and spokes)

• Standard for computer networks since the

1990’s

• Becoming more and more popular in

Industrial settings

• Uses twisted pair data cables terminated in

8P8C (sometimes incorrectly called RJ45)

modular plugs, wired according to TIA/EIA-

568-B

Twisted Pair Cables

• Twisting a pair of wires that act as a communication

channel will:

– Minimize the loop area between the pair (minimize the

self-inductance and capacitance)

– Which in turn tends to cancel out much of the

electromagnetic interference from external sources and

crosstalk from adjacent pairs

– Improve the efficiency of the channel

PLC Special Features

• Time Delay Relays

• Counter Relays

• Special Functions

• User Defined Functions

• Special Bits

Time Delay Relays

• When TD Relay Pick-Up Coil is Energized,

a Delay is Initiated

• Normally Open Contacts Wait to Close

until Delay is Completed

• Normally Closed Contacts Wait to Open

until Delay is Completed

• Very Useful for Creating a Sequence of

Control Events

Making Use of Delays • Delay Motor Start While Alarm Sounds for

Safety

Counters • Counter Relays must “Count” a pre-

determined number of events before

changing contact status

• Can Count Up (UpCounter) or Count Down

(DownCounter)

• e.g. An UpCounter is set to 8 and is

programmed to detect every occurrence of a

5 Volt pulse. When it has detected 8 such

occurrences, the NO Contacts close and the

NC contacts open.

• Great for making Real-Time Clocks, etc

Special Functions

• Modern PLCs can perform many Math and

Logic Functions without additional Ladder

Logic Programming

– Differentiation, Integration

– +, -, *, /

– Boolean Logic Functions (AND, NOT, OR)

– Master Control Functions (Reset, etc)

Motor Protection

• Essential Part of Motor Control

• Protect against:

– Under Voltage

– Under Frequency (AC Machines Only)

– Over Current

– Over Heating

– Over Speed

– Over Load

Motor Protection Schemes

• Incorporated Directly in Ladder Logic

Control Schemes

ELECTRIC TRACTION

INTRODUCTION:

The locomotion in which the driving force is

obtained from electric motor is called the electric

traction system.

There are various system of electric traction

existing such as electric train, trolley buses,

diesel-electric vehicles and gas turbine electric

vehicles

ELECTRIC TRACTION SYSTEM

MAJOR CLASSIFICATIONS OF

TRACTION

Non-electric traction:

examples

steam engine drive

ic engine drive

Electric traction:

examples

diesel electric drive

gas turbine electric drive

REQUIREMENTS OF AN IDEAL TRACTION

SYSTEM

The starting tractive effort should be high so as

to have rapid acceleration.

The wear on the track should be minimum.

The equipments should be capable of

withstanding large temporary loads.

Speed control should be easy.

Pollution free.

Low initial and maintenance cost.

The locomotive should be self contain and able to

run on any route.

MERITS OF ELECTRIC TRACTION

High starting torque.

Less maintenance cost

Cheapest method of traction

Rapid acceleration and braking

Less vibration

Free from smoke and flue gases hence used for

underground and tubular railway.

DEMERITS OF ELECTRIC TRACTION

High capital cost.

Problem of supply failure.

The electrically operated vehicles have to move

on guided track only.

Additional equipment is required for achieving

electric braking and control.

DIFFERENT SYSTEMS OF TRACTION:

Direct steam engine drive

Direct IC engine drive

Steam electric drive

IC engine electric drive

Petrol electric traction

Battery electric drive

Electric drive

IC ENGINE ELECTRIC DRIVES

SUPPLY SYSTEMS FOR ELECTRIC

TRACTION:

D.C system

A.C system

Single phase

Three phase

Composite system

Single phase AC to DC

Single phase to three phase

SPEED TIME CURVE FOR TRAIN MOVEMENT

Acceleration

Constant acceleration

Speed curve running

Free run or constant speed period

Coasting period

Retardation or braking period

TYPICAL SPEED TIME CURVES FOR

DIFFERENT SERVICES

Urban or city services

Sub urban services

Main line services

TYPES OF SPEED IN TRACTION

crest speed

Average speed

Schedule speed

FACTORS AFFECTING ENERGY

CONSUMPTION

Distance between the stops.

Train resistance

Acceleration and retardation.

Gradient

train equipment.

TRACTION MOTORS

DC series motor

Ac series motor

Three phase induction motor

TRACTION MOTOR ELECTRICAL FEATURES

High starting torque

Simple speed control

Regenerative braking

Better commutation

Capability of withstanding voltage fluctuations.

MECHANICAL FEATURES

Light in weight.

Small space requirement.

Robust and should be able to withstand

vibration.

TRACTION MOTOR CONTROL

Rheostat control

Series parallel control

Field control

Buck and boost method

Metadyne control

Thyristor control

Phase control

Chopper control

BRAKING

ELECTRIC BRAKING

Plugging or reverse current braking

Rheostatic braking

Regenerative braking

DC shunt motor

DC series motor

Induction motor

MECHANICAL BRAKING

Compressed air brakes

Vacuum brakes

MAGNETIC TRACK BRAKES

RECENT TRENDS IN ELECTRIC TRACTION

Tap changer control

Thyristor control

Chopper control

Micro processor control

MICRO PROCESSOR CONTROL

QUESTIONS ?

“If fail to Plan, you plan to fail”

THANK

YOU