LEESON Chassis Mount PWM Control: 175292.00 - Manual (Page 30)

IR COMPENSATION (IR COMP)
The IR COMP setting determines the degree to which motor speed
is held constant as the motor load changes. It is factory set for
optimum motor regulation.
Use the following procedure to recalibrate the IR COMP setting :
1. Set the IR COMP trimpot to minimum (full CCW).
2. Rotate the speed adjust potentiometer until the motor runs at
midspeed without load (for example, 900 RPM for an 1800 RPM
motor). A hand held tachometer may be used to measure
motor speed.
3. Load the motor armature to its full load armature current rating.
The motor should slow down.
4. While keeping the load on the motor, rotate the IR COMP
trimpot until the motor runs at the speed measured in step 2. If
the motor oscillates (overcompensation), the IR COMP trimpot
may be set too high (CW). Turn the IR COMP trimpot CCW to
stabilize the motor.
5. Unload the motor.
24 Calibration