Electric Machine Daily Quiz #20

One alternator with the waveform 220 sin 50t is to be connected across another alternator with the waveform 220 cos 50t. Choose correct option-

1. Synchronisation will be bump-less
2. Synchronisation will be bump-less if the polarity of the incoming one is taken care of.
3. Synchronisation is not possible even if phase sequence and polarity conditions are satisfied.
4. None of the above

The lamp/ bulb rating used for the synchronisation by dark lamp method should be-

1. Equal to phase to neutral voltage
2. Equal to line to line voltage
3. Equal to double of phase to neutral voltage
4. Equal to double line to line voltage

Synchronisation by rotating lamp method is also known as-

1. One bright, two dark lamp method
2. One dark, two bright lamp method
3. Siemens Halske method
4. 2,3
5. None

The needle of synchronoscope moves slightly anticlockwise. What does it indicate about the frequency of incoming alternator?

1. Less frequency
2. More frequency
3. Equal to the existing alternator
4. No conclusion

The synchronising power is maximum when-

1. Load is resistive i.e. upf load
2. Load is not applied
3. Load is reducing
4. Load is added