單項(xiàng)選擇題Pedestal cranes have limit switches to restrict movement of which function（s）（）.

A.Hoist upper & lower limits
B.Luff travel limits
C.Rider block hoist upper & lower limits
D.All of the above


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1.單項(xiàng)選擇題On no account（）to be exceeded.

A.is the SWL of the crane
B.are the SWL of the crane
C.the SWL of the crane is
D.the SWL of the crane are

3.單項(xiàng)選擇題Most pedestal crane power is provided by（）.

A.Electro-hydraulic units
B.Steam units
C.Independent internal combustion power units
D.All of the above

4.單項(xiàng)選擇題If an attempt is made to hoist a load that exceeds the capacity of an electric winch，an overload safety device causes a circuit breaker to cut off the current to the winch motor（）.

A.when the line pull reaches the rated winch capacity
B.after the line pull exceeds the rated winch capacity
C.after a short build-up of torque
D.immediately

5.單項(xiàng)選擇題How should you signal the crane operator to move slowly（）.

A.Use one hand to give any motion signal，and place the other hand motionless in front of the hand giving the motion signa
B.Extend arm with the thumb pointing up，and flex the fingers in and out for as long as the load movement is desired
C.First tap your elbow with one hand and then proceed to use regular signals
D.First tap the top of your head with your fist and then proceed to use regular signals