Hello friends, today I am going to tell you Why Alternators are Synchronized, Synchronizing method of alternators : If you also want to know, then keep reading this article completely.
Why Alternators are Synchronized
It is not possible to generate a large amount of electrical power through a single alternator in power plants. In large power plants, electrical power is produced by operating more than one alternator in parallel.
Running two or more alternators in parallel is called synchronizing. In two alternators connected in parallel, when one alternator cannot supply, the other alternator gives continuous supply. The first alternator is called the running machine, and the new alternator is called the incoming machine.
The following conditions are to be fulfilled before the alternator is connected in parallel.
1. The terminal voltage of both the alternators connected in parallel should be identical.
2. The frequency (f) of both the alternators should be identical.
3. The phase sequence of the new alternator should be the same as the phase sequence of the running alternator.
The regulator in the series order of the alternator field is adjusted to satisfy the first condition. By regulating the field excitation, the terminal voltage of the new alternator is equal to the bus-bar voltage.
The speed of the prime mover of the alternator is adjusted to satisfy the second condition.
N=120xf/P
According to the third condition, the ends of the 3-phase attached to the bus bar of the running alternator should be the same ends of the new alternator.
Synchronizing method of alternators
Synchronizing is the method of connecting 3-PHASE alternators in parallel sequence or connecting multiple alternators to a standard bus bar. The synchronization methods of 3-PHASE alternators are as follows.
1.Dark lamp method
2.Bright lamp method
3.Dark and Bright lamp method
4.Passionata fate (Synchroscope method)
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Dark Lamp Method
In this method, each phase of the incoming machine R’, Y, B’ and each phase of the bus bar between R, Y, B respectively, a lamp pair connected in series, across the TP switch goes.
Now the TP of the incoming machine. All lamp pairs are checked for extinguishing before switching on as follows:
(i) Lamp pairs keep on going off – there is a difference in frequency of both the alternators. Make the frequency of both machines equal by adjusting the rotation speed of the prime-mover of the incoming machine. When the frequency is the same, the lamp pair is extinguished.
(ii) Lamp pairs do not go on and off together – the phase-order of both the alternators is different. Correct the phase-order by interchanging the combination of any two of the three phases of the incoming machine.
(iii) Lamp pairs burn slowly – there is a difference in the voltage of both the alternators. Adjust the voltage with the field regulator of the incoming machine so that all three lamp pairs are extinguished.
(iv) All three lamp pairs are completely extinguished – both the alternators are synchronized. TP of incoming machine Turns the switch on.
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Now you must know Why Alternators are Synchronized, Synchronizing method of alternators.