Rockwell Automation DC3N DC Drive User Guide, 1/4-2HP-115/230 VAC - Manual (Page 37)

29 Calibration
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.
To calibrate IR COMP (exact calibration):
1. Turn the IR COMP trimpot full CCW.
2. Set 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.
Approximate calibration:
If the motor does not maintain set speed as the load changes, gradually rotate the
IR COMP trimpot CW. 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 speed.
See Figure 16 for recommended IR COMP settings.