KB Electronics KBIC-240DS - Manual (Page 19)

19
FIGURE 8. IR TRIMPOT RANGE
3 V
0
(Factory Set to 3 Volts DC for
Controls with 90 Volt DC Output)
(Factory Set to 6 Volts DC for
Controls with 180 Volt DC Output)
7.5 IR Compensation Trimpot (IR):
IR compensation is provided to substantially improve
load regulation. If the load presented to the motor
does not vary substantially, the IR adjustment may
be set at a minimum level (approximately 1/4 of full
setting). The control is factory adjusted to
approximately 3% regulation. If superior performance
is desired (less than 1% speed change of base
speed from 0 to full load), then the IR compensation.
should be adjusted (See Figure 8) as follows:
Note: Excessive IR comp. will cause control to become
unstable, which causes motor cogging.
Notes: 1.The correct value Plug-In Horsepower Resistor ® must be installed for the IR Compensation to
operate properly. Calibration of the IR Trimpot is normally not required when the proper Plug-In
Horsepower Resistor
® is installed. (Actual Comp. voltage depends on the value of the Horsepower
Resistor®) 2. Excessive IR Compensation will cause the motor to become unstable, which causes
cogging.
To Recalibrate the IR Trimpot:
1. Set the IR Trimpot to approximately 25% rotation.
2. Run the motor unloaded at approximately 1/3 speed and record the RPMs.
3. Run the motor with the maximum load and adjust the IR Trimpot so that the motor speed under
load equals the unloaded speed recorded in step 2.
4. Remove the load and recheck the RPMs.
5. If the unloaded RPM has changed, repeat steps 2 - 4 for more exact regulation. The control is now
compensated to provide minimal speed change due to changing loads.