3.
Increase the boost until the ammeter reaches the nameplate rated current (Amps AC).
4.
Using the Main Speed Potentiometer, slowly adjust the motor speed over a 0 – 15 Hz
(0 – 450 RPM) range. If the motor current exceeds the nameplate rating, decrease the
boost setting.
13.7 Motor Overload (I
2
t) with RMS Current Limit (CL)* –
Sets the current limit (overload), which
limits the maximum current to the motor, prevents motor burnout, and eliminates nuisance
trips. The CL Trimpot is factory set to 160% of the drive rating. To increase the current limit,
rotate the CL Trimpot clockwise. To decrease the current limit, rotate the CL Trimpot counter-
clockwise. See Figures 28 – 32, on page 43.
*UL approved as an electronic overload protector for motors.
In order to ensure that the motor is properly protected with the I
2
t feature, it is required
that the CL Trimpot be set for 160% of the motor nameplate rating. This is accom-
plished as follows:
Note:
This adjustment must be made within 6 seconds or the I
2
t Trip will occur.
1.
Wire an AC RMS ammeter in series with one motor phase.
2.
Set the CL Trimpot fully counterclockwise.
3.
Adjust the speed setting to 30% of full speed.
4.
Lock the motor shaft and adjust the CL Trimpot to 160% of the motor nameplate rating.
Example: A 1/2 HP motor has a full load current rating of 1.8 Amps. Set the CL Trimpot to
1.8 X 160% = 2.9 Amps.
42
