Copyright Goodheart-Willcox Co., Inc.
454 Hydraulic Systems for Mobile Equipment
7. In what time era did variable-displacement
LSPC pumps begin appearing in agriculture
equipment?
A. Late 1950s-early 1960s.
B. Late 1960s-early 1970s.
C. Late 1970s-early 1980s.
D. Late 1980s-early 1990s.
8. What is the name of the valve that has the
responsibility of choosing the higher cylinder
working pressure, either from the rod end or
the cap end of a double-acting cylinder?
A. Primary shuttle.
B. Secondary shuttle.
C. Intermediate shuttle.
D. None of the above.
9. What is the name of the valve that has the
responsibility of choosing the higher working
pressure between two different DCVs?
A. Primary shuttle.
B. Secondary shuttle.
C. Intermediate shuttle.
D. None of the above.
10. A tractor with an LSPC hydraulic system has
a total of 4 DCVs, with no hitch and no power
beyond. How many total primary shuttle
valves are required?
A. Three.
B. Four.
C. Five.
D. Six.
11. A tractor with an LSPC hydraulic system has
a total of 4 DCVs, with no hitch and no power
beyond. How many total secondary shuttle
valves are required?
A. Three.
B. Four.
C. Five.
D. Six.
12. Technician A states that LSPC systems can
use fixed-displacement pumps. Technician B
states that LSPC systems can use variable-
displacement pumps. Who is correct?
A. Technician A.
B. Technician B.
C. Both A and B.
D. Neither A nor B.
13. An LSPC hydraulic system with a plugged
orifice in the signal network will exhibit
what?
A. Only low system pressure.
B. Only moderate system pressure.
C. Only high system pressure.
14. All of the following can be used to describe
an unloading valve’s spring, EXCEPT:
A. margin.
B. differential.
C. standby.
D. stall.
15. All of the following are required for a gear
pump and two DCVs to be used in a load-
sensing system, EXCEPT:
A. closed-center DCVs.
B. unloading valve.
C. pressure-reducing valves.
D. shuttle valves.
16. All of the following are required for a
pressure-compensated DCV to operate a
bidirectional motor, EXCEPT:
A. closed-center DCV.
B. unloading valve.
C. pressure-reducing valve.
D. shuttle valve.
17. An inline axial variable-displacement pump
that is used in an LSPC torque-limiting
hydraulic system has how many control
spools (used for controlling the pump flow
and pressure)?
A. Zero.
B. One.
C. Two.
D. Three.
18. What is a common system pressure in an
LSPC hydraulic system when the control
valves are in the neutral position?
A. 300–550 psi.
B. 550–1000 psi.
C. 1000–1500 psi.
D. 2000–2500 psi.