Danfoss LDU21C Service Manual page 11

Service Manual
LDU21C Closed Circuit Axial Piston Transmission
Operation
Control
©
Danfoss | April 2025
Charge Pressure Relief Valve settings for external charge supply
LDU 21C
Charge Pressure Relief Valve Function
Charge Flow
P400550
Direct Displacement Control
The LDU21C features Direct Displacement Control (DDC) .The swashplate angle is set directly by a control
lever or linkage attached directly to the swashplate control arm. Control lever movement changes the
speed and rotating direction of the motor by increasing or decreasing the swashplate angle.
The swashplate control arm can be located on ether left or right hand side of the LDU21C.
Control Handle Requirements
Maximum allowable control arm torque is 35 N•m [309.8 lbf•in]. The approximate torque necessary to
rotate the control arm at 200 bar system operating pressure and 3000 rpm is 15 N•m with the standard
valveplate. The actual value will vary due to the influence of pump operating conditions.
Input shaft rotation
Control arm location
Control arm rotation
Output rotation
High pressure port
Low pressure port
For high pressure port and low pressure port, see installation drawings of Technical Information
BC282717470618.
Flow l/min [US gal/min]
10.8 [2.9]
CW
Right Left
CW CCW CW
CCW CW CW
MA MB MB
MB MA MA
CCW
Right
CCW CW CCW
CCW CW CCW
MA MB MA
MB MA MB
AX342138485422en-000102 | 11
Left
CW CCW
CCW CW
MA MB
MB MA