A.Contactors control current and relays control voltage
B.A relay is series connected and a contactor is parallel connected
C.Contactors can handle heavier loads than relays
D.Contactors are made from silver and relays are made from copper
您可能感興趣的試卷
你可能感興趣的試題
A.short proof
B.ground proof
C.explosion proof
D.overload proof
A.prime mover speed
B.exciter output voltage
C.load on the alternator
D.number of poles
A.shunt field
B.circuit breaker
C.metal framework
D.inter-pole
A.brushes
B.slip rings
C.commutators
D.all of the above
A.is usual
B.is not usual
C.is necessary
D.is not impossible
最新試題
When does auxiliary burner of incinerator put into operation? （）Ⅰ. start incinerator when it is coldⅡ. the sludge for dealing with is littleⅢ. the sludge for dealing with is largeⅣ. the water and impurity in sludge are too muchⅤ. the temperature in incinerator is lowⅥ. dealing with little solid rubbish
One of the reasons that cause oil flowed from sludge outlet of a self-cleaning separator is（）
Which one is NOT the ‘clear grounds’ for a more detailed inspection?（）
The additional mark （）in the Classification Certificate for Machinery means propulsion apparatus is remotely controlled on the navigating bridge control station, and engine assembly control station is unmanned periodically.
A purge recovery system is used in a centrifugal air conditioning or refrigeration system to （）
If two A.C.generators are to be operated in parallel, the load is distributed evenly by（）
Under MARPOL Code the ship to which it applies has to carry （）
Which of the diesel engine components listed increase air density and helps to improve engine operating efficiency?（）
Cold weather starting of a diesel engine may be made easier by（）
Which of the following items don’t belong to dock repair works?（）