| 1. | Thermal overload relays are used to protect the motor against over current due to ? | |
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grounds
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short-circuits
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heavy loads
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all of the above
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Report Question| 2. | Circuit breakers are essentially ? | |
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arc extinguishers
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current carrying contacts called electrodes
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transformers to isolate the two systems
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circuits to break the system
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| 3. | Burden of a protective relay is the power ? | |
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absorbed by the circuit of relay
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required to operate the circuit breaker
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developed by the relay circuit
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none of the above
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| 4. | The line insulation is ...... the insulation level of the station equipment ? | |
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less than
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proportional to
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same as
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not directly related with
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| 5. | Induction cup relay is operated due to changes in ? | |
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impedance
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voltage
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current
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all of the above
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| 6. | Short-circuit currents are due to ? | |
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two phase to ground faults
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single phase to ground faults
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three phase faults
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any of these
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| 7. | The torque produced in induction type relay (shaded pole structure) is ? | |
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inversely proportional to the square of the current
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proportional to square of the current
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inversely proportional to the current
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proportional to the current
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| 8. | H.R.C. fuse, as compared to a rewirable fuse, has ? | |
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high speed of operation
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high rupturing capacity
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no ageing effect
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all of the above
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| 9. | A fuse is never inserted in ? | |
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phase line
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positive of D.C. circuit
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negative of D.C. circuit
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neutral wire
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| 10. | To limit short-circuit current in a power system ..... are used ? | |
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H.R.C. fuses
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earth wires
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reactors
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isolators
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