A circuit breaker differs from a fuse in that a circuit breaker ______.A.melts and must be

A circuit breaker and a fuse have a basic similarity(类似) in that they both ______.

A.can be reset to energize the circuit

B.should open the circuit when overloaded

C.will burn out when an over current flow develops

D.should short the circuit when overloaded

A.电路板断路器

B.电路板控制器

C.电路板装置

D.电路板箱

A circuit breaker and a fuse have a basic similarity in that they both______.

A.can be reset to energize the circuit

B.should open the circuit when overloaded

C.will burn out when an over current flow develops

D.should short the circuit when overloaded

Fuses placed in series with a thermal trip-type circuit breaker are used for _____.

A.time-delay protection

B.short-circuit protection

C.short duration surge protection

D.sustained overload protection

When securing an AC generator, you should FIRST _____.

A.open the generator circuit breaker

B.switch the voltage regulator to "manual"

C.decrease the field excitation to minimum

D.reduce the load on the unit

A.De-energize the applicable switchboard bus

B.Bypass the interlocks

C.Secure and tag the supply circuit breaker in the open position

D.Station a man at the circuit supply switch

A.increase

B.not change

C.decrease

D.be exactly 60 hertz

A ground in an electrical circuit outside the engine room _____.

A.cannot be detected tinder normal conditions

B.is of no consequence to engineering personnel

C.is indicated at the branch circuit breaker panel

D.is indicated by the ground detecting lamps on the main switchboard

A.the circuit breaker

B.for leaks in the suction piping

C.relief valve .is not properly seated

D.the suction strainer

If the electric motor driving an air compressor fails to start, the cause may be a _____.

A.leaking unloader

B.tripped circuit breaker

C.control line leak

D.defective pop valve