Related Questions

Thermal overload relays are used to protect the motor against over current due to
A short-circuits
B heavy loads
C grounds
D all of the above
Switches and relays should be shown in this position with no operating force or applied energy:
A Normal
B Closed
C Offset
D Application
Which of the following relays is used on long transmission lines?
A Impedance relay
B Mho's relay
C Reactance relay
D None of the above
The phase lag produced by transportation relays
A Is independent of frequency
B Is inversely proportional to frequency
C Increases linearly with frequency
D Decreases linearly with frequency
Discrimination between main and back up protection is provided by the use of relays which are
A fact
B sensitive
C slow
D none of the above
The inverse definite mean time relays are used for over current and earth fault protection of transformer against
A heavy loads
B internal short-circuits
C external short-circuits
D all of the above
Directional relays are based on flow of
A power
B current
C voltage wave
D all of the above
Relays can be designed to respond to changes in
A resistance, reactance or impedance
B voltage and current
C light intensity
D temperature
E all above
Relays are used for phase faults on long line.
A Impedance
B Reactance
C Either of the above
D None of the above
Protective relays are devices that detect abnormal conditions in electrical circuits by measuring
A current during abnormal condition
B voltage during abnormal condition
C constantly the electrical quantities which differ during normal and abnormal conditions
D none of the above

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