Overload relays are of_______________type

A. induction
B. solid state
C. thermal
D. electromagnetic

A thermal protection switch can protect against_____________?

A. short-circuit
B. temperature
C. overload
D. over voltage

SF6 gas______________?

A. is yellow in colour
B. is lighter than air
C. is nontoxic
D. has pungent small

Which of the following medium is employed for extinction of arc in air circuit breaker?

A. water
B. oil
C. air
D. sf6

On which of the following routine tests are conducted ?

A. oil circuit breakers
B. air blast circuit breakers
C. minimum oil circuit breakers
D. all of the above

The arcing contacts in a circuit breaker are made of______________?

A. copper tungsten alloy
B. porcelain
C. electrolytic copper
D. aluminium alloy

Arc in a circuit behaves as_______________?

A. a capackive reactance
B. an inductive reactance
C. a resistance increasing with voltage rise across the arc
D. a resistance decreasing with voltage rise across the arc

Fault diverters are basically____________?

A. fuses
B. relays
C. fast switches
D. circuit breakers

Magnetic circuit breaker has ___________ trip action

A. delayed
B. instantaneous
C. both of the above
D. none of the above

Thermal circuit breaker has____________?

A. delayed trip action
B. instantaneous trip action
C. both of the above
D. none of the above