field controller for DC drive
FXMP25 Field Controller
  • Overview
  • Specifications
  • Downloads

The FXMP25 external field controller may be connected digitally to a Mentor MP using a standard RJ45 connection, allowing setup by standard drive parameters.

The FXMP25 can also function in standalone mode using its integrated keypad and display.


Every Mentor MP has a motor field controller as standard that provides excellent field control for the majority of DC motors. However, in the following situations, the optional FXMP25 external field controller is recommended: 

  • The required field current is greater than that offered by the standard drive, up to 25 A. For example, older motors with low field voltages.
  • The field is required to be forced down more quickly than is possible with a standard half controlled field bridge. For example, on spindle motors or motors with high field time constants where the field is required to weaken more quickly than the natural time constant of the field winding.
  • FXMP25 allows applications to be implemented with simple field current reversal, without armature reversal. For example, applications where a rapid change in torque direction is not required. With the Mentor MP it is possible to implement a four quadrant system with a two quadrant armature converter where a slow change in torque direction can be tolerated.


Easy upgrade

The new FXMP25 replaces our existing FXM5 option. It may also be controlled digitally by a Mentor II, allowing set-up by standard drive parameters. The FXMP25 has the same physical dimensions as the existing FXM5, but extends its current range to 25 A.

High current fields

For field currents above 25 A, a separate Mentor MP DC drive can be used as a field controller.


Continuous AC input: 26 A

Continuous DC output current: 25 A

Inputs and Outputs





Digital input


Field economy level


Analog input


Current demand input

0 to 10V

Analog output


Field current output signal
Armature voltage output signal

0 to 10V



Fail relay

Normally open and normally closed

Overall dimensions 

Height: 247 mm (9.72 in)
Width: 192.38 mm (7.57 in) Depth: 90.27 mm (3.55 in)



Case Studies



Product Catalog

Technical Documents and Software

White Papers