Because the swashplate is biased to maximum angle, the pump attempts to deliver full flow to the
hydraulic system. When the flow being delivered exceeds demand, the pressure delta across the ECV is
great enough to overcome spring force and shift the LS spool porting system pressure to the servo
piston. The pump de-strokes reducing flow until the delta across the ECV becomes equal to the LS
setting. When flow being delivered is less than demand, the delta across the ECV drops below the LS
setting and the LS spring shifts the spool connecting the servo piston to pump case. The pump strokes
increasing flow until the delta across the ECV becomes equal to the LS setting.
When the external control valve is placed in neutral, it connects the LS signal line to drain. With no LS
pressure acting on the non-spring end of the LS spool, the pump adjusts stroke to whatever position
necessary to maintain system pressure at the LS setting. The pump is now in standby mode.
Because of the series arrangement of the LS and PC spools, the PC spool will override the LS spool. If at
any time system pressure reaches the PC setting, the PC spool will shift blocking the passage that
connects the LS spool with the servo piston and porting system pressure to the servo piston causing the
pump to de-stroke.
Electronic Controls
PLUS+1
®
Compliance
All Series 45 Electric controls have met and passed the Danfoss PLUS+1
®
compliance standard testing,
and as such, this Series 45 control is PLUS+1
®
compliant. PLUS+1
®
compliance blocks are available on the
Danfoss website, within the PLUS+1 Guide section.
Electric Proportional Control Principle
The Electric Proportional Control consists of a proportional solenoid integrated into a Remote Pressure
Compensated control. This control allows the pump to be operated at any pressure limit between the
Load Sense and Pressure Compensation settings by varying the current sent to the solenoid.
Electric On-Off Control Principle
The Electric On/Off Control consists of an On/Off solenoid integrated into a Remote Pressure
Compensated control. This control allows the pump to be operated at either the Load Sense pressure
setting when On, or the Pressure Compensation pressure setting when Off.
Service Manual
Series 45 Frame K2 Open Circuit Axial Piston Pumps
Features
©
Danfoss | April 2017
AX00000301en-US0101 | 13
