你可能感興趣的試題

單項(xiàng)選擇題

Increased internal leakage, in addition to poor hydraulic system response,and inadequate lubrication, is the result of （）.

A.pump bearings in poor condition
B.excessively worn actuator-piston packing
C.broken directional control valve centering springs
D.low hydraulic oil viscosity

單項(xiàng)選擇題

Most solenoid valves are actuated by （）.

A.a spring
B.an electromagnet
C.the force of gravity
D.refrigerant pressure

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