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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 (I2t) with RMS Current Limit (CL)* –
Sets the current limit (overload),
which limits the maximum current to the motor, prevents motor burnout, and eliminates nui-
sance 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
counterclockwise. See Figures 28-29, on page 43.
*UL approved as an electronic overload protector for motors.
In order to ensure that the motor is properly protected with the I2t feature, it is
required that the CL Trimpot be set for 160% of the motor nameplate rating. This is
accomplished 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.
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