41
5.
Adjust the COMP Trimpot until the loaded RPM is equal to the unloaded RPM.
6.
The motor is now compensated to provide constant speed under varying loads.
13.6 boost (DEC/b) –
When the drive is set for 50 Hz Motor Operation (Jumper J1 installed in the
“50Hz” position), the DEC/B Trimpot automatically becomes the adjustable BOOST Trimpot.
Most 60 Hz motors conforming to NEMA standards can operate from a preset Volts/Hz curve.
50 Hz motors, however, generally differ widely in their characteristics. Therefore, it is neces-
sary to have adjustable Boost to obtain maximum motor performance.
To increase the boost, rotate the BOOST Trimpot clockwise. To decrease the boost, rotate the
BOOST Trimpot counterclockwise. See Figure 27, on page 40.
In order for the 50 Hz motor to run properly, the boost must be adjusted. If the application
does not require full torque below 10 Hz, the Boost (DEC/B) Trimpot can be conservatively set
at 8% (9 o’clock position).
Note:
In 50 Hz motor operation, the deceleration time is automatically set to the same as the
Acceleration Trimpot (ACC) setting.
WARnInG! To avoid motor winding heating and failure, do not overboost
the motor.
The boost (DEC/b)Trimpot may be adjusted as follows:
1.
Wire an AC RMS ammeter in series with one motor phase.
2.
Run the motor unloaded at approximately 4 Hz (or 120 RPM).
Note:
An unloaded motor with excessive boost will draw more current than a partially
loaded motor.
