Copyright Goodheart-Willcox Co., Inc.
Chapter 18 Load-Sensing Pressure-Compensating (LSPC) Hydraulic Systems 455
19. What type of pressure will an LSPC
hydraulic system have in the stall mode?
A. Zero pressure.
B. Low pressure.
C. Moderately average pressure.
D. High pressure.
20. When an LSPC system is running a hydraulic
motor, signal pressure plus margin pressure
equals _____.
A. pump outlet pressure
B. working pressure
C. regulated pressure
D. relief pressure
21. Anytime pump outlet pressure is directly
connected to signal pressure what will occur?
A. Standby mode.
B. Working mode.
C. Stall mode.
D. Carryover mode.
22. In a traditional LSPC variable-displacement
pump equipped with two spools, what is the
name of the small spool that has a hydraulic
port for connecting a hydraulic line?
A. Pressure compensator spool.
B. Torque-limiting spool.
C. Flow control spool.
23. When actuated, a signal valve (sometimes
called a jammer valve) does what
hydraulically in an LSPC system?
A. Puts the system in a low-pressure
standby.
B. Connects case pressure to signal pressure.
C. Connects pump outlet pressure to signal
pressure.
D. Lowers pump outlet pressure.
24. Which of the following systems has the
ability to provide either high pressures
or high flows for a given amount of
horsepower?
A. Open-center.
B. Pressure compensating.
C. Load sensing pressure compensating.
D. LSPC and torque limiting.
25. Within a torque-limiting LSPC pump,
which of the following components has the
responsibility of conveying the angle of the
swash plate?
A. Pressure compensator spool.
B. Flow control spool.
C. Sensing piston.
D. Bias piston.
26. Power beyond is being added to an LSPC
hydraulic system. What else must be added?
A. An extra shuttle valve.
B. A relief valve.
C. Torque-limiting controls.
D. A variable-displacement pump.
27. Looking at a PQ graph, the corner
horsepower point illustrates what system
condition?
A. Minimum pressure, minimum flow.
B. Maximum pressure, maximum flow.
C. Wasted horsepower.
D. Usable horsepower.
28. A variable-displacement LSPC hydraulic
system that uses a jammer solenoid for all
of its functions can eliminate which of the
following from the system?
A. Signal network.
B. Flow control valve.
C. Pressure compensator valve.
D. Hydraulic pump.
29. An LSPC DCV has a manual detent kickout.
The DCV’s primary shuttle will send oil to all
of the following, EXCEPT:T T
A. DCV detent kickout.
B. pressure compensator valve.
C. DCV secondary shuttle.
D. main system relief valve.
30. Which one of the following systems will
consume the least amount of horsepower
when the DCVs are in a neutral position?
A. Traditional open-center system.
B. Pressure-compensating system.
C. Fixed-displacement LSPC system.
D. Variable-displacement LSPC system.