If a centrifugal pump is driven by a constant speed electric motor and produces a discharge pressure less than designed, the cause is probably ______.A.excessive pump speedB.excessive suction headC.worn wearing ringsD.gross pump misalignment

题目

If a centrifugal pump is driven by a constant speed electric motor and produces a discharge pressure less than designed, the cause is probably ______.

A.excessive pump speed

B.excessive suction head

C.worn wearing rings

D.gross pump misalignment

相似考题

1.The disadvantage of the non－synchronous motor is that it requiresoand it produces a low starting－torqueA.much initial currentB.direct currentC.little initial currentD.constant current

2.A hydraulic motor may be driven by______.A.an electric motorB.a diesel engineC.a compressorD.oil

3.这些舱盖通常是用电力或液压驱动的。（）A、These hatches are usually driven by electric or hydraulic power.B、These hatch covers are usually driven by electric or hydraulic power.C、These hatch covers are usually driven by electric.D、These hatch covers are usually driven by hydraulic power.

4.In an AC.synchronous motor electric propulsion plant,propeller speed is controlled by()A.prime mover speedB.number of energized main motor polesC.propulsion generator field strengthD.electric coupling field strength

更多“If a centrifugal pump is driven by a constant speed electric motor and produces a discharg ”相关问题

  • 第1题：

    单选题
    If the pump for a hydraulic anchor windlass is overheating, the cause may be （）.
    A

    excessive drive motor speed

    B

    excessive pump discharge pressure

    C

    too low of a tilting box angle

    D

    insufficient drive motor speed


    正确答案： A
    解析： 暂无解析

  • 第2题：

    单选题
    Which of the following statements is correct with regards to the operation of a centrifugal cargo pump?（）
    A

    Oil is discharged from the impeller through the outlet

    B

    Gravity causes the oil to flow toward the discharge

    C

    The self-priming feature of the centrifugal pump enables it to draw its own suction as it starts

    D

    The discharge capacity varies directly with the speed of the impeller


    正确答案： C
    解析： 暂无解析

  • 第3题：

    单选题
    A variable displacement system of hydraulic drives consists of （）.
    A

    a variable displacement axial piston pump

    B

    a constant displacement axial piston pump

    C

    a reciprocating piston pump

    D

    a centrifugal pump


    正确答案： B
    解析： 暂无解析

  • 第4题：

    单选题
    An AC synchronous transmission type remote steering control system consists of a （）.
    A

    transmitter at the steering station and a receiver at the steering engine

    B

    reversible motor at the steering station geared to the steering pumps

    C

    small induction motor on the bridge which controls the redder through pulleys

    D

    variable displacement hydraulic pump driven by a reversible DC motor


    正确答案： C
    解析： 暂无解析

  • 第5题：

    单选题
    Increasing the speed of a centrifugal pump will result in an increase in its capacity Another means of increasing the capacity of a centrifugal pump is to increase the （）.
    A

    diameter of the discharge piping, with all other factors remaining the same

    B

    diameter of the suction piping, with all other factors remaining the same

    C

    width of the impeller only

    D

    diameter of the impeller


    正确答案： B
    解析： 暂无解析

  • 第6题：

    单选题
    If a centrifugal pump is driven by a constant speed electric motor and produces a discharge pressure less than designed, the cause is probably（）.
    A

    excessive pump speed

    B

    excessive suction head

    C

    worn wearing rings

    D

    gross pump misalignment


    正确答案： D
    解析： 暂无解析

  • 第7题：

    单选题
    Lube oil pumps taking suction from the sump of most small marine engines are usually （）.
    A

    of the diaphragm type

    B

    of the centrifugal type

    C

    of the positive displacement type

    D

    independently driven by electric motors


    正确答案： D
    解析： 暂无解析

  • 第8题：

    单选题
    If a hydraulic pump on a winch accidentally stops while hoisting，the load will stay suspended because（）.
    A

    a check valve will close that prevents reverse circulation

    B

    a centrifugal counterweight counteracts the force of gravity

    C

    the electric pump motor will cut out

    D

    the control lever will move to the stop position


    正确答案： A
    解析： 暂无解析

  • 第9题：

    单选题
    Which features of a centrifugal pump reduce the need for renewing worn impellers and pump casings?（）
    A

    Close radial clearance between impeller hub and casing

    B

    Low rotational speed of impeller

    C

    Removable end plate

    D

    Replaceable impeller and casing wearing rings


    正确答案： C
    解析： 暂无解析

  • 第10题：

    单选题
    On modern ships, centrifugal pump with a self-primer has replaced reciprocating pump as bilge pump because（）
    A

    centrifugal pump is cheaper than reciprocating pump

    B

    the size of centrifugal pump with same capacity is smaller than that of reciprocating pump

    C

    centrifugal pump makes maintenance easier than reciprocating pump does

    D

    all of the above


    正确答案： B
    解析： 暂无解析

  • 第11题：

    单选题
    Fuel oil transfer systems used onboard diesel propelled vessels are required to have （）.
    A

    two fuel oil transfer pumps provided where one is to be independent of the main engine

    B

    two fuel oil transfer pumps, with a combined capacity exceeding the maximum consumption of the main engine

    C

    engine driven transfer pumps and only used in constant speed applications

    D

    the capacity of the engine driven pump exceed the consumption rate of the engine to which it is attached


    正确答案： D
    解析： 暂无解析

  • 第12题：

    单选题
    The amount of fluid delivered by a centrifugal pump can be regulated by （）.
    A

    throttling the pressure line

    B

    changing the speed of the rotor

    C

    either A or B

    D

    None of the above is tree


    正确答案： A
    解析： 暂无解析

  • 第13题：

    单选题
    If an electric motor driven air compressor fails to start, it may be due to a （）.
    A

    leaking discharge valve

    B

    jammed suction valve

    C

    tripped overload relay

    D

    broken discharge un-loader


    正确答案： D
    解析： 暂无解析

  • 第14题：

    单选题
    A hydraulic motor may be driven by （）.
    A

    an electric motor

    B

    a diesel engine

    C

    a compressor

    D

    oil


    正确答案： A
    解析： 暂无解析

  • 第15题：

    单选题
    操作完后，关掉电动机。（）
    A

    After operation, start the electric motor.

    B

    Before operation, stop the electric motor.

    C

    Before operation, start the electric motor.

    D

    After operation, stop the electric motor.


    正确答案： D
    解析： 暂无解析

  • 第16题：

    单选题
    Before attempting to put out a class “C” fire involving an electric-driven centrifugal pump, you should FIRST （）.
    A

    insulate your shoes

    B

    ground the fire hose

    C

    secure its power supply

    D

    start the fire pump


    正确答案： D
    解析： 暂无解析

  • 第17题：

    单选题
    Increasing the speed of a centrifugal pump will result in an increase in its capacity in its capacityAnother means of increasing the capacity pump is to increase the（）
    A

    diameter of the discharge piping, with all other factors remaining the same

    B

    diameter of the suction piping, with all other factors remaining the same

    C

    width of the impeller only

    D

    diameter of the impeller


    正确答案： C
    解析： 暂无解析

  • 第18题：

    单选题
    When there is a fire in a large electric motor, normally the very FIRST step is to （）
    A

    secure the electric supply

    B

    ventilate area to remove smoke

    C

    start the fire pump and lead out hose

    D

    apply foam


    正确答案： C
    解析： 暂无解析

  • 第19题：

    单选题
    Excessive air leakage into the suction side of a centrifugal pump would be indicated by which of the following operational problems?（）
    A

    The pump delivers full capacity when started, but gradually slackens off toan abnormally low flow

    B

    The pump packing gland overheats after short operating periods

    C

    The motor over-current protective device continually shuts the pump down

    D

    Pounding noises can be heard at the pump suction chest


    正确答案： B
    解析： 暂无解析

  • 第20题：

    单选题
    A centrifugal pump produces the required pressure energy by means of a rotating （） provided with vanes.
    A

    propeller

    B

    impeller

    C

    circumference

    D

    screw


    正确答案： A
    解析： 暂无解析

  • 第21题：

    单选题
    In a fixed displacement axial piston hydraulic motor, the speed is varied by（）
    A

    regulating the ratio between torque and speed via the torque limiter at the motor

    B

    directing the motor output flow through a bypass line

    C

    maintaining a constant flow and pressure input

    D

    controlling the input flow rate


    正确答案： C
    解析： 暂无解析

  • 第22题：

    单选题
    What type of electric motor is most commonly used on board ship?（）
    A

    non-synchronous electric motor

    B

    synchronous electric motor

    C

    fully enclosed electric motor

    D

    watertight electric motor


    正确答案： C
    解析： 暂无解析

  • 第23题：

    单选题
    The hand steering is a method by which the motion of the rudder is controlled with （）.
    A

    a motor-driven steering wheel

    B

    a pneumatic steering wheel

    C

    a hand-driven steering wheel

    D

    an electric steering wheel


    正确答案： C
    解析： 暂无解析

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