Page 212 - Electrician - TT (Volume 1)
P. 212
ELECTRICIAN - CITS
• EMF commutation to some extent armature reaction
• Interpoles are provided only for improving commutation
• The LPT is strengthened by Interpole TPT
• Machine with Interpole has 25% more capacity
Parallel operation of dc generators
Advantages of parallel operation
- Continuity of service
- Efficiency
- Maintenance and repair
- Increasing plant capacity
- Non-availability of single large unit
Conditions of parallel operation
• Same voltage
• Same polarity
• Power rating need NOT be the same
Parallel operation of dc shunt generator
• generator 1 is connected &supplying to the load.
• Now generator 2 is to be connected in parallel.
• Start the prime mover of the generator 2
• Adjusted its speed is to the rated value.
• Close the switch S4 .
• The voltmeter connected across S2 measures voltage
• Adjust excitation of the generator 2 till the voltmeter reads zero.
• The zero on the voltmeter ensures that the voltage of incoming generator 2 is same as that of generator 1 or
the bus bar voltage.
• closed the switch S2which connects the incoming generator 2 in parallel with the system.
199
CITS : Power - Electrician & Wireman - Lesson 30-37