Hello Kreutz,
UHU Servo controller manual says: "...voltage of the output stage has to be 15% higher than the voltage specified on the motor to provide maximum performance" I have done this because this was written so.
My motors are made servo especially the big one has a back cap with the encoder mounted inside, wires coming out from a connector. I doubt that lowering the PS voltage from 65 to 55 will make any significant difference.

Originally Posted by kreutz
and it is also normal for the motor to heat up more when idling
I thought motors should heat up more when loaded rather than at idle.

What is the purpose of the RLC network that you have used?

Thanks, Todor