Operation; Pressure Limiter Valves; Pressure Limiter Sectional View - Danfoss H1P 045 Service Manual

Service Manual
H1P 045/053/060/068 Axial Piston Single Pumps

Operation

Pressure Limiter Valves

© Danfoss | June 2020
Pressure limiter valves provide system pressure protection by compensating the pump swash plate
position when the set pressure of the valve is reached. A pressure limiter is a non-dissipative (non heat
generating) pressure regulating system.
Each side of the transmission loop has a dedicated pressure limiter valve that is set independently. A
pump configured with pressure limiter must have pressure limiters on both sides of the system pressure
loop. The pump order code allows for different pressure settings to be used at each system port.
The pressure limiter setting is the maximum differential pressure between the high and low loops. When
the pressure limiter setting is reached, the valve ports oil to the low-pressure side of the servo piston. The
change in servo differential pressure rapidly reduces pump displacement. Fluid flow from the valve
continues until the resulting drop in pump displacement causes system pressure to fall below the
pressure limiter setting.
An active pressure limiter destrokes a pump to near neutral when the load is in a stalled condition. The
pump swash-plate moves in either direction necessary to regulate the system pressure, including into
stroke (overrunning) or over-center (winch payout).
The pressure limiter is optional on H1 pumps (except H1T 045/053 tandem pumps).

Pressure Limiter Sectional View

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