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    Quiz on Chapter 8: Air and Hydraulic Pumps

    Dec. 17, 2006
    1. A rule of thumb for air compressor output for each input horsepower is: 2 scfm @ 100 PSI 3 scfm @ 100 PSI 4 scfm @ 100 PSI 2. Large air compressors load and unload as pressure drops and builds. Small air compressors: do the same. ...

    1. A rule of thumb for air compressor output for each input horsepower is:

    1. 2 scfm @ 100 PSI
    2. 3 scfm @ 100 PSI
    3. 4 scfm @ 100 PSI

    2. Large air compressors load and unload as pressure drops and builds. Small air compressors:

    1. do the same.
    2. never build enough pressure.
    3. turn on at a minimum pressure and off at a maximum pressure.

    3. A hydraulic pump produces:

    1. flow in gallons per minute (gpm).
    2. pressure in pounds per square inch (psi).
    3. both of the above.

    4. A positive-displacement pump:

    1. cannot turn if the outlet is blocked.
    2. can turn with the outlet blocked.
    3. can only turn with the outlet blocked.

    5. Gear pumps:

    1. can be variable volume.
    2. cannot be variable volume.
    3. can be pressure compensated.

    6. Vane pumps:

    1. can be variable volume.
    2. cannot be variable volume.
    3. cannot be pressure compensated.

    7. Piston pumps .

    1. can be variable volume.
    2. cannot be variable volume.
    3. cannot be pressure compensated.

    8. An open-center circuit:

    1. blocks pump flow in the center condition.
    2. does not have a center condition.
    3. allows pump flow to go to tank in center condition.

    9. A closed-center circuit:

    1. blocks pump flow in the center condition.
    2. does not have a center condition.
    3. allows pump to go to tank in center condition.
    10. The symbol at right is a:
    1. pressure-compensated variable-volume pump.
    2. fixed-volume pump.
    3. bi-directional pump.
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    11. While the input shaft of a bi-directional pump is turning in one direction of rotation, it:

    1. can move fluid from either port.
    2. can only move fluid from one port.
    3. must have a suction line hooked to tank.

    12. Wobble-plate piston pumps:

    1. must rotate in the opposite direction to reverse flow.
    2. can reverse flow while turning the same way.
    3. cannot reverse flow at anytime.

    13. Swash-plate piston pumps:

    1. have moveable or fixed-angle swash plates.
    2. are always bi-directional.
    3. can only move fluid one way.

    14. Bent-axis pumps :

    1. cannot be fixed volume.
    2. operate better at higher vacuum inlet.
    3. cannot be bi-directional flow.

    15. Load-sensing pumps:

    1. operate at load pressure plus load-sense bias spring pressure.
    2. operate at compensator pressure at all times.
    3. cannot be variable volume.

    16. Horsepower- and torque-limiting pumps:

    1. use extra horsepower all the time.
    2. use minimum horsepower all the time.
    3. never use more than a preset horsepower regardless of pressure.

    17. Pump shaft alignment is not important at any time.

    1. True
    2. False

    18. Closed-loop circuits:

    1. use a makeup pump to keep the loop full.
    2. must have extra large flow lines to keep the pump from cavitating.
    3. cannot reverse the direction of an actuator.

    19. A pump-motor adapter is:

    1. a device to keep the pump from cavitating.
    2. a unit to match pump horsepower to motor horsepower.
    3. a device to directly attach a pump to an electric motor.

    20. Cavitation is caused by:

    1. too little fluid volume at the pump inlet.
    2. too much fluid volume at the pump inlet.
    3. too much fluid volume at the pump outlet.

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