单项选择题
In an electro-hydraulic steering gear system, when will the variable displacement pump be placed on stroke?（）
A.When the helm is at any angle other than amidships
B.When the six-way valve is opened
C.When the ram relief valves lift
D.When the redder angle is different from the position of the helm
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相关考题
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单项选择题
An additive used to improve the ability of a lube oil to reduce friction is known as a/an （）.
A.suppressant additive
B.dispersant additive
C.extreme pressure additive
D.viscosity improver additive -
单项选择题
The suction - force principle of operation is a typical characteristic of （）.
A.centrifugal pumps
B.jet pumps
C.propeller pumps
D.reciprocating pumps -
单项选择题
Air leakage between the shaft and stuffing box packing in a centrifugal pump is prevented by （）.
A.a compressed packing gland
B.lantern tings between the packing rings
C.a liquid seal
D.the stuffing box gland
