Page 81 - CITS - Electrician - Trade Practical

ELECTRICIAN - CITS

EXERCISE 33 : To study the characteristics of series,

shunt & compound Generators

Objectives

At the end of this exercise you shall be able to:
• check the terminals & connections of series, shunt and compound Generators
• start & run the series, shunt and compound Generators and build up the voltage
• apply the load on Generators and study the performance characteristics
• plot the characteristics graph and compare series, shunt and compound Generators.

Requirements

Tools/Equipments/Instruments
• Combination Plier 165mm, • Ammeter MC, 20 A -1 No.
insulated -1 No. • Multi meter Digital, 3 digit -1 No.
1/2
• Screw Driver 150mm, insulated -1 No. • Rheostat 700 Ω, 5A -1 No.
• Neon Tester 75mm, 500 V -1 No. • Tacho meter 3000 RPM -1 No.
• Electrician knife insulated -1 No. Materials/Components
• MG set (AC to DC) with DOL • Test lamp 60 W, 230 V -1 No.
starter,DC compund Generator • DPST switch 250 V, 32 A -1 No.
5 KW, 250 V -1 No. • Connecting wire 2.5 sq.mm - as reqd.
• Lamp load 5 KW, 250 V -1 No. • Cotton waste / cloth - as reqd.
• Voltmeter MC, 250 V -1 No.
• Ammeter MC, 5 A -1 No.

Procedure

TASK 1 : Check the MG set details & terminals
1 Check the MG set and read specifications of motor & generator.
2 Check and identify the terminals of motor & generator.
3 Draw the connection diagram of loading of DC series, shunt and compound generators.

TASK 2: Study the characteristics of DC Series Generator
1 Make the connections of Prime mover AC motor and DC series Generator with voltmeter, Ammeter and output
DPST switch.
2 Check the connections, start the prime mover AC motor coupled to DC series Generator and Observe induced
voltage recorded in the voltmeter. (There will be no induced voltage, since series generator is to be started
with load)

3 Switch OFF the prime mover motor, and connect the lamp load across generator terminals through DPST
switch as per circuit diagram.
4 Now start the prime mover AC motor coupled to DC series Generator, close the DPST switch and switch ON
the lamp load gradually.
5 Observe & record the induced voltage in voltmeter. Further increase the load until rated current of generator
and record the induced voltage & load / field current.

6 Reduce the load gradually, switch OFF the load switch and stop the prime mover motor.
7 Plot the characteristics graph of generator.

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