KB Electronics KBWT-210 - Manual (Page 6)

KBWT Series Installation and Operation Instructions (A40130) – Rev. B00 – 5/29/2013
Page 6 of 7
To Recalibrate the CL Trimpot:
1 Disconnect the AC power and wire a DC ammeter in series with either motor armature lead.
Note: If only an AC ammeter is available, wire it in series with either AC line input lead.
2 Set the Main Speed Potentiometer to approximately 30 – 50 % clockwise position.
3 Set the CL Trimpot fully counterclockwise. The CL LED will illuminate red.
4 Lock the motor shaft (be sure the CL Trimpot is set fully counterclockwise).
5 Apply power and rotate the CL Trimpot clockwise until the desired current reading is observed on the DC
ammeter. Factory Current Limit setting is 1.5 times the full load rating of the motor (with a DC ammeter wired
in series with the motor armature). If using an AC ammeter wired in the AC line input, the factory Current Limit
setting will read 0.75 times the full load rating of the motor. Do not exceed 2 times motor current rating
(maximum clockwise position).
Note: Steps 4 and 5 must be completed within 3 seconds or the Timed Current Limit (TCL) will trip the drive. If the
drive trips in TCL the drive must be restarted (either with the On/Off AC Line Switch or the Inhibit Switch).
Warning! Do not leave motor shaft locked for more than 2 – 3 seconds or motor damage may result.
6.2 IR Compensation Trimpot (IR): The IR Trimpot sets the amount of compensating voltage required to keep
the motor speed constant under changing loads. If the load does not vary substantially, the IR Trimpot may be set
to a minimum level (approximately 1/4 of full clockwise rotation). The IR Trimpot is factory set to provide 6 Volts of
compensation for Models KBWT-16, 26 and 3 Volts of compensation for Models KBWT-110, 112, 210.
To increase the amount of compensating voltage, rotate the IR Trimpot clockwise. To decrease the amount of
compensating voltage, rotate the IR Trimpot counterclockwise. See Figure 11, on page 5.
Note: 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.
6.3 Maximum Speed Trimpot (MAX): The MAX Trimpot sets the maximum speed of the motor when the Main
Speed Potentiometer is set fully clockwise. The MAX Trimpot is factory set to 100% of base motor speed.
To increase the maximum speed, rotate the MAX Trimpot clockwise. To decrease the maximum speed, rotate the
MAX Trimpot counterclockwise. See Figure 12, on page 5.
Caution! Do not set the maximum speed above the rated motor RPM since unstable motor operation may occur.
6.4 Minimum Speed Trimpot (MIN): The MIN Trimpot sets the minimum speed of the motor when the Main
Speed Potentiometer is set fully counterclockwise. The MIN Trimpot is factory set to 0% of base motor speed.
To increase the minimum speed, rotate the MIN Trimpot clockwise. To decrease the minimum speed, rotate the
MIN Trimpot counterclockwise. See Figure 13, on page 5.
6.5 Acceleration Trimpot (ACCEL): The ACCEL Trimpot is provided to allow for a smooth start over an
adjustable time period each time the AC power is applied or the Main Speed Potentiometer is adjusted to a higher
speed. The ACCEL Trimpot is factory set to 2 seconds, which is the amount of time it will take for the motor to
accelerate from zero speed to full speed. To increase the acceleration time, rotate the ACCEL Trimpot clockwise.
To decrease the acceleration time, rotate the ACCEL Trimpot counterclockwise. See Figure 14, on page 5.