10-10-2012, 05:52 PM
To Synchronise the Three phase alternators by using Synchroscope
To Synchronise the Three phase alternators by using Synchroscope.pdf (Size: 164.22 KB / Downloads: 145)
Synchronising of Alternators:-
The process of connecting an alternator in parallel with another alternator or with common bus bars
is known as synchronizing. The conditions to be satisfied for synchronising are -
(i) Terminal voltages should be equal.
(ii) Frequency of EMF generated should be equal.
(iii) Phase sequence of each alternator should be same.
Stepwise Procedure :-
A) For synchronisation of alternators
1. Switch ON Main supply.
2. Switch ON both MCB ( if applicable).
3. Adjust the DC voltage to rated value with dimmer of DC motor set 1.
4. Start the DC Motor with three point starter.
5. Adjust the speed of DC motor up to rated speed by field control.
6. Give the excitation to set 1 and adjust the AC voltage of alternator 1 to rated value as
indicated on the digital voltmeter on the panel or analog voltmeter on work table.
7. Adjust the speed and check the frequency as indicated by digital / analog frequency
meter on the panel or work table.
8. Switch ON the contactor 1( if applicable).
9. Adjust the DC voltage to rated value with dimmer of DC motor set 2.
10. Start the DC Motor with three point starter.
11. Adjust the speed of DC motor up to rated value by field control.
12. Give the excitation to set 2 and adjust the AC voltage of alternator 2 to rated value as
indicated on the digital voltmeter on the panel or analog voltmeter on the work table.
13. Adjust the speed and check the frequency as indicated by digital frequency meter on
the panel or analog meter on work table.
14. Switch ON the contactor 3 (if applicable).
For load sharing by two alternators
1. Follow the steps 1 to 18 as in part A.
2. Switch ON the load by closing contactor 5 (if applicable).
3. Gradually increase the load in steps and take reading of load shared by both the
alternators.
4. Change the excitation and observe the load sharing between alternator 1 and 2.
5. Switch OFF the load.
6. Reduce the excitation of both alternators to zero.
7. Reduce the voltage across the DC motor to zero.
8. Switch OFF both the motors.
Conclusion :-
1. Two alternators can be synchronized when the required conditions are satisfied.
2. Load sharing between two alternators is possible if they are operated in parallel.
3. If the excitation of alternator is increased then load shared is
4. If the excitation of alternator is decreased then load shared is