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.
- never build enough pressure.
- turn on at a minimum pressure and off at a maximum pressure.
3. A hydraulic pump produces:
- flow in gallons per minute (gpm).
- pressure in pounds per square inch (psi).
- both of the above.
4. A positive-displacement pump:
- cannot turn if the outlet is blocked.
- can turn with the outlet blocked.
- can only turn with the outlet blocked.
5. Gear pumps:
- can be variable volume.
- cannot be variable volume.
- can be pressure compensated.
6. Vane pumps:
- can be variable volume.
- cannot be variable volume.
- cannot be pressure compensated.
7. Piston pumps .
- can be variable volume.
- cannot be variable volume.
- cannot be pressure compensated.
8. An open-center circuit:
- blocks pump flow in the center condition.
- does not have a center condition.
- allows pump flow to go to tank in center condition.
9. A closed-center circuit:
- blocks pump flow in the center condition.
- does not have a center condition.
- allows pump to go to tank in center condition.
- pressure-compensated variable-volume pump.
- fixed-volume pump.
- bi-directional pump.
11. While the input shaft of a bi-directional pump is turning in one direction of rotation, it:
- can move fluid from either port.
- can only move fluid from one port.
- must have a suction line hooked to tank.
12. Wobble-plate piston pumps:
- must rotate in the opposite direction to reverse flow.
- can reverse flow while turning the same way.
- cannot reverse flow at anytime.
13. Swash-plate piston pumps:
- have moveable or fixed-angle swash plates.
- are always bi-directional.
- can only move fluid one way.
14. Bent-axis pumps :
- cannot be fixed volume.
- operate better at higher vacuum inlet.
- cannot be bi-directional flow.
15. Load-sensing pumps:
- operate at load pressure plus load-sense bias spring pressure.
- operate at compensator pressure at all times.
- cannot be variable volume.
16. Horsepower- and torque-limiting pumps:
- use extra horsepower all the time.
- use minimum horsepower all the time.
- never use more than a preset horsepower regardless of pressure.
17. Pump shaft alignment is not important at any time.
- True
- False
18. Closed-loop circuits:
- use a makeup pump to keep the loop full.
- must have extra large flow lines to keep the pump from cavitating.
- cannot reverse the direction of an actuator.
19. A pump-motor adapter is:
- a device to keep the pump from cavitating.
- a unit to match pump horsepower to motor horsepower.
- a device to directly attach a pump to an electric motor.
20. Cavitation is caused by:
- too little fluid volume at the pump inlet.
- too much fluid volume at the pump inlet.
- too much fluid volume at the pump outlet.