单项选择题
The output volume of a positive fixed displacement pump can be changed only by （）.
A.changing the angle of the tilting plate
B.changing the speed of the pump
C.moving the slide block and rotor
D.moving the shaft trunnion block
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相关考题
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An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.
A.oil foaming in the compressor
B.higher than normal suction and discharge pressures with a higher box temperature
C.higher than normal discharge pressure with a normal box temperature
D.the compressor to run continuously -
单项选择题
When the steering gear is in operation, you should （）.
A.check hydraulic oil levels every hour
B.check the rams for overheating
C.check for excessive oil leakage from rams
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单项选择题
The oil in a cargo winch gear box should be sampled periodically to （）.
A.prevent the gear box from leaking
B.prevent the oil from becoming inflammable
C.make sure it has not become contaminated
D.make sure the motor bearings are lubricated
