2 6
Calibration
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.
Recalibrate the IR COMP setting when using a lower current rated motor. Refer to the
recommended IR COMP settings in Figure 12 on page 27 or recalibrate using the
following procedure:
1. Set the IR COMP trimpot to minimum (full CCW).
2. Rotate the speed adjust potentionmeter 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.
