Overheating of relay contacts or contact born out is due to
A. slow making and breaking of load circuit contacts
B. foreign matter on the contact surface
C. too low contact pressure
D. all of the above
Answer: Option D
Related Questions on Switchgear Protections
Magnetic circuit breaker has ______ trip action.
A. delayed
B. instantaneous
C. both of the above
D. none of the above
In a circuit breaker the basic problem is to
A. maintain the arc
B. extinguish the arc
C. transmit large power
D. emit the ionizing electrons
The arcing contacts in a circuit breaker are made of
A. copper tungsten alloy
B. porcelain
C. electrolytic copper
D. aluminium alloy
Air blast circuit breaker is used for
A. over currents
B. short duty
C. intermittant duty
D. repeated duty
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