Electrical Machines Lab Manual

LABORATORY WORK BOOK

Electrical Machines

Department of Electronic Engineering Lahore College for Women University, Lahore

Electrical Machines Laboratory Work Book

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CONTENTS

Sr.

No. Experiment Name

1 Record the no load voltage generated by a DC generator under

constant speed and separate excitation.

2 Record the magnetization characteristics of a generator with series

excitation.

3 Record of external characteristics of spark excitation D.C generator.

4

Record of the regulation characteristics of separate excitation D.C generator

5

Record of the external characteristics of D.C shunt excitation

generator

6 Record of the external characteristics of D.C series generator

7 Record of the external characteristics of the short shunt dynamo

8 Record the external characteristics of the different compound

generator

9 Record the magnetization characteristics of 3 phase alternator (No.

Load test

10 Record the permanent short –characteristics of 3 phase alternator

11 Record the voltage variation at the alternator terminals for different

load

12

Determine the mechanical and Iron loses of the dynamo by means of

switches, s method.

The dynamo operates as no load motor.

13 Start the motor with separate excitations. Record the operation

characteristic of motor.

14 Start the motor (D.C) with shunt excitation

Record the operation characteristic of the motor


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Experiment No.1

Purpose: -

Record the no load voltage generated by a DC generator under constant

speed and separate excitation. Components D.C compound Motor/Shunt generator set.

• D.C compound Motor 4 point, starter an control board. • D.C volt and ammeter on control panel excitation. • D.C supply 0~230v D.C for separate excitation. • Optical Tachometer • Supply leads.

Electrical Circuit Diagram

Procedure

• Connect the D.C compound Motor to 4 point starter on the control

board

• Connect the D.C generator armature winding to the generator terminal

on control panel

• Connect the D.C generator field winding to D.C field excitation

regulator terminal on the control panel

• And set the regulator knob at zero position

• Switch on the main circuit breaker on the panel

• Switch on the D.C main circuit breaker and 4 point starter supply switch

and start the motor

• Record the speed by tachometer

• Record the magnetization characteristic by measuring the voltage "V"

delivered of the value of excitation current 'Ie' obtained by acting on the

control knob and shown in the table

• A first measurement with increasing current and with decreasing

current to see the magnetic hysteretic effect on terminal voltage.


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Experiment – 2

Purpose

Record the magnetization characteristics of a generator with series excitation.

Components

• D.C shunt motor I D.C series motor set

• D.C 3 point starter an control panel

• D.C voltmeter and ammeter on control panel

• D.C supply 0~230v D.C for series field excitation

• Optical Tachometer

• Supply leads


Procedure

• Connect the D.C shunt Motor to 3 point starter on the control panel

• Connect the D.C series generator armature winding to the series

generator terminal on control panel

• Connect the D.C field (series) winding to D.C field excitation regulator terminal on the control panel and set the regulator knob at zero position

• Switch on the main circuit breaker on the panel

• Switch on the D.C main circuit breaker and 3 point switch to the on

position Start the motor with help of 3 point motor starter and record

the speed by Tachometer

• Record the magnetizing characteristics by measuring the voltage 'V'

delivered by the generator in correspondence acting on the control

knob and shown in table

• A first measurement with increasing current and de with decreasing

current to see the magnetic hysteretic effect on terminal voltage.


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Experiment - 3

Purpose

Record of external characteristics of spark excitation D.C generator

Components

• D.C compound motor I D.C shunt generator set

• D.C Compound motor 4 point starter on control panel

• D.C volt and ammeter on control panel

• D.C supply 0~230v D.C for separate excitation


• Supply leads

• Resistance load


Procedure


panel.

• Connect the D.C generator armature winding to the generator terminals on control panel.

• Connect the D.C generator field winding to D.C field excitation regulator terminal on the control panel and set the regulator at zero position.

• Switch on the main circuit breaker.

• Switch on the D.C main circuit breaker and 4 point supply switch to the on position.

• Start the motor with the help of 4 point starter.

• Record the speed of generator by tachometer

• Set the field current' I.e.' of D. C generator 0.4 'A' and record the terminal voltage no load voltage

• Measure the voltage for every value of the load current delivered by the generator, obtained by suitably adjusting the selector switches s1,s2,s3 and s4 and record the readings in the table


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Experiment – 4

Purpose !

Record of the regulation characteristics of separate excitation D.C generator Components

• D.C compound motor / D.C shunt generator set

• D.C compound motor 4 point starter control panel

• D.C volt and ammeter on control panel

• D.C supply 0~ 23v D.C for separate excitation

• Resistance load


Procedure

• Connect the D.C compound Motor to 4 point starter on the control panel

• Connect the D.C generator armature winding to the generator terminals on control panel

• Connect the D.C generator field winding to D.C field excitation on the

control panel and set the regulator at zero position.

• Switch on the main circuit breaker.

• Switch on the D.C main circuit breaker and 4 point supply switch in

ON position Start the motor with the help of 4 point starter.

• Record the speed of generator by tachometer.

• Record the regulation characteristics by measuring the excitation

current that is necessary to keep the voltage at the generator terminal

constant as in function of the load current.

• With null load (e=0) adjust the excitation in current 'Ie' in such a way

that the delivered voltage is equal, to V=200V.

• Connect the load step by step and keep the terminal voltage constant

by varying the field current.

• Record the recordings in the table.


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Experiment – 5

Purpose

Record of the external characteristics of D.C shunt excitation generator.

Components

• D.C compound motor / D.C shunt generator set

• D.C Compound motor starter 4 point on control panel

• D.C volt meter / ammeter in the control panel


• Resistance load


Procedure


panel

• Connect the D.C generator armature winding to the generator terminals

on control panel

• Connect the D.C generator field winding to the armature terminal A1 to

F1 and A2 to F2

• Switch on the D.C main "C" "B" 4 point supply switch on the control

panel Start the motor with the help of 4 point starter


• Record the external characteristics generator by measuring the voltage

'V' at the terminals as a function of load current

• Connect the load resistance step by step suitably adjusting the selector

switch S 1, S2, S3 and S4

• Record the recordings in the table

• After completing experiment all the circuit breaker and switch turn off


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Experiment – 6

Purpose

Record of the external characteristics of D.C series generator

Components

• D.C compound motor / D.C series generator set

• D.C Compound motor starter 4 point on the control panel

• D.C volt meter and ammeter on control panel


• Resistance load

•


procedure

• Connect the D.C compound Motor to the 4 point starter on the control

panel

• Connect the D.C series generator terminal on the control panel

• Switch on the main A.C supply C.B

• Switch on the D.C main CB and 4 point 3upply switch in on the control

panel

• Start the motor with the help of 4 point starter


• Record the external characteristics of the generator by measuring the

voltage 'V' at the terminals as the function of the load current I

• Connect the load resistance on the panel terminal and increase the

load step by step

• Record the recordings in the table

• After completing the experiment turn OFF all switch and circuit breaker


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Experiment – 7

Purpose

Record of the external characteristics of the short shunt dynamo

Components

• D.C shunt motor / D.C compound generator set .

• D.C Compound motor starter 3 point on the panel .

• D.C volt ammeter on the control panel


• Resistance load (Resistive load)

• Supply leads

Electrical circuit diagram

procedure

• Connect the D.C compound generator terminal on the control panel


• Connect the resistive load on the control panel to load terminal


• Switch on the D.C main "CB" and 3 point starter supply switch on the

control panel



• Record the external characteristics of the generator by measuring the

voltage 'V' at the terminals and the shunt excitation current as a

function of the load current I. Measure terminal voltage 'V' at no load.

• Switch on the load starter switch and increase the load step by step

• Record the readings and fill the table • After completing experiment turn OFF all the switch and circuit breaker

.


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Experiment - 8

Purpose

Record the external characteristics of the different compound generator

Components

• D.C shunt motor / D.C compound generator set

• D.C shunt motor 3 point starter on the control panel

• D.C volt meter I ammeter on the control panel


• Resistance load (Resistance load)

• Supply leads


Procedure

• Connect the D.C shunt motor to 3 point starter on the control panel


and change the polarity of series winding

• Connect the resistive load on the control panel


• Switch on the D.C main "CB" and 3 point starter


• Record now external characteristics with different series excitation

current Ie as a function of the load current I.

• Measure terminal voltage as no load.

• Switch on the load selector switch and increase the load step by step

• Record the readings and fill the table

• After completing experiment OFF all the switch and circuit breaker


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Experiment - 9

Purpose

Record the magnetization characteristics of the 3 phase alternator (No. Load

test)

Components

• D.C shunt machine I 3phase alternator

• D.C shunt motor shatter 3 point starter on the panel

• D.C / A.C voltmeter I ammeter on the control panel


• Supply leads

Electrical circuit diagram

Procedure

• Connect the D.C motor to the 3 point starter on the panel

• Connect the alternator field wind on the panel to field excitation

terminal and set the regulator to zero position

• Connect the alternator terminal U,V W to A,B,C phase tern1inal on the

panel Switch on the main A.C supply C-B

• Switch on the D.C main ‘CB" and 3 point starter switch to ON position

• Starter the motor with the help of point starter

• Record the speed of alternator by tachometer

• Record the magnetization characteristics finally by measuring the

voltage 'V' delivered by the alternator at constant rated speed in

correspondence of the values of the excitation current le


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• Record the reading and fill the table

• After completing the experiment turn OFF all the switch and circuit breaker


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Experiment -10

Purpose

Record the permanent short-circuit characteristics of 3 phase alternator

Components

• D.C compound motor /3 phase alternator set

• D.C 4 point starter on the control panel

• D.C / A.C volt / ammeter on the control panel

• D.C supply 0~230V D.C on the control panel


• Supply leads


Procedure

• Connect the D.C motor to the 4 point starter on the panel

• Connect the alternator field wind on the panel to field excitation

terminal and set the regulator to zero position.

• The alternator terminal U, V, W through short


• Switch on the D.C main and 4 point starter switch to on position



• For rated speed of alternator current the motor field wind to field

regulator terminal and set to 0-4 A current and run the alternator at

rated speed.

• Start to excite the alternator with the variable voltage 0-60V so to

carryout the values of the excitation .current le delivered from the short

circuit armature Record the readings and fill the table

• After completing experiment turn OFF all the switch and circuit breaker


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Experiment - 11

Purpose

Record the voltage variation at the alternator terminals for different load.

Components

• D.C compound motor /3 phase alternator set

• D.C compound 4 point starter on the panel

• D.C / A.C volt / ammeter on the control panel

• D.C supply 0-220V on control panel


• Resister loads


Procedure

• Connect the D.C motor to 4 point starter on the panel

• Connect the motor field wind to the field regulator on panel board and

set current 4A

• Connect the alternator field wind to the regulator on the control panel

and set it zero position

• Connect the 3 phase supply terminal on the constant penal A, B, C

terminal

• Switch on the main A.C supply C-B

• Switch on the D.C main and 4 point starter switch to ON position


Record the rated speed of alternator by adjusting the regulator D.C

motor field tachometer

• Excite the alternator with the variable voltage 0-220V. so that no load


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voltage delivered at the rated speed is equal to the value of rated

voltage V=220V. • Without modifying any longer the value of the alternator excitation

current connect the three phase load.

• Increase the load step by step by switching the S 1, S2, S3 and S4

switch and record the value voltage V and current Le delivered from

the alternator kept at its rated speed

• After completing the experiment turn OFF all the switch and circuit

breaker


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Experiment - 12

Purpose Determine the mechanical and Iron loses of the dynamo by means of shinbone’s method. The dynamo operates as no load motor. . Components

• D.C shunt motor

• D.C supply 0-220 V.1A,on control panel

• D.C supply 0-220v-3A on control panel

• D.C ammeter / Volt meter on control panel


• Supply leads


procedure

• To connect the D.C motor Armature to the D.C 0-220V 3A supply on

the panel

• Connect the D.C motor field wind to the D.C Q-220V.1 a supply on

control panel

• Switch on the main supply circuit breaker

• Switch on the D.C supply switch

• Excite the D.C field winding at O1lA-p verify that the machine excited

• Slowly increase the armature voltage 'V' by means of D.C supply regulator knob until the machine is set to rotation

• Adjust the armature voltage to 100V and therefore reduce the excition

current le by means of the D.C field supply knob until the speed results

about 1500RPM

• Adjust in the same time the armature voltage and the excitation

current until the speed of 1500 RPM with armature voltage of 220V • Measure the armature current I and the excitation current le and write

the values in the following table • Now increase in the same time the armature voltage 'V' and the

excitation current le in such a way to obtain the armature other voltage


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values shown in the table,

• With constant speed, for every voltage value that is shown • Stop the machine by resting the armature voltage and therefore set the

regulator knob at zero position


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Experiment – 13

Purpose

Start the motor with separate excitations Record the operation

characteristic of motor

Components

• D.C shunt motor with mechanical break

• D.C motor 4 point starter

• D.C supply 0-230v on control panel • D.C voltmeter / ammeter on control panel • Optical Tachometer • Supply leads


Procedure

• Connect the D. C motor armature winding the 4 point starter , • Connect D.C motor field winding the D.C field excitation regulator

terminal on the control panel • Set the mechanical breaks spring balance scale at

zero position • Switch on the main circuit breaker on the control panel

• Switch on the D.C main circuit breaker and 4 point starter supply

suitable

• Switch on the D.C field regulator supply and set the D.C motor field

wind current at. 4A

• Start the motor by help of 4 point starter

• Record the rated speed of the motor

• The motor is therefore loaded by step by step by mean of Mechanical

breaks, the load is carried at by moving the secrew on the mechanical

break and note the reading until the motor fall load current reached its

rated value

• Of record the reading the experiment switch


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Experiment – 14

Purpose

Start the D.C motor with series excitations Record the operation characteristic of the motor.

i

Components

• D.C series motor with mechanical break

• D.C 2 point starter on the control panel

• D.C volt / ammeter on the control panel • Optical digital Tachometer

• Supply leads Electrical Circuit Diagram

• Connect the D.C series motor to the 2 point starter on the

control panel.

• Connect the D.C volt meter / ammeter according to electrical

diagram

• Set the mechanical break : spring balance at zero position

• Switch on the main circuit breaker on the control panel

• Switch on the D.C main circuit breaker and 2 point starter supply switch on position

• Start the motor with the help of 2 point starter on the control panel

• Record the motor speed by tachometer

• The motor is therefore loaded by step by step by mean of mechanical

breaks, the load is carried at by moving the secrew on the mechanical

breaks and note the reading until the motor fall load current reached its

rated value

• Record the reading the table

Electrical Machines Lab Manual

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