32
Calibration
IR COMPENSATION (IR COMP)
The IR COMP trimpot 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 curernt
rated motor. See Figure 17 (page 34), for typical IR COMP
trimpot settings, or recalibrate using the following procedure:
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.
