Danfoss APP 46 Installation, Operation And Maintenance Manual page 74

Operating guide
3. High torque on electric motor
Cause
3.1 Too high outlet pressure from pump
3.2 Pump starts against pressure
3.3 Constant torque
74 | 180R9407 | AQ274347577038en-000902
Installation, Operation and Maintenance APP 21-46 pumps
Remedy
3.1.1 Check uid salinity.
3.1.2 Check temperature.
3.1.3 Check pressure drop across RO membrane.
3.2.1 Check that electric motor is correctly
sized.
3.2.2 Check internal parts (see item 2.1).
3.2.3 Systems with more than one electric
motor installed:
Start motors simultaneously.
3.3.1 Please contact Danfoss High Pressure
Pumps sales o ce.
Comments
Pump conditions may change (more salt, lower
water temperature or scaling of RO membrane)
causing higher pressure, resulting in higher
motor torque.
Pumps run in parallel with cascade start, may
switch o the motor relay due to too high
torque caused by high outlet pressure.
If the electric motor is too small for the APP, APP S
or APP S 674 pump, it cannot provide su cient
torque.
© Danfoss | 2023.03