24
The slip compensation may be adjusted as follows:
1.
Connect an AC RMS ammeter in series with one
motor phase.
2.
Run the motor and set the unloaded speed to
approximately 50% (900 RPM on 4-pole
1500/1725 RPM motors).
3.
Using a tachometer, record the unloaded speed.
4.
Load the motor to the nameplate rated current
(AC Amps).
5.
Adjust the COMP Trimpot until the loaded RPM is
equal to the unloaded RPM.
6.
The motor is now compensated to provide con-
stant speed under varying loads.
7.6 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 necessary 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 32.
In order for the 50 Hz motor to run properly, the boost must be adjusted. If the applica-
tion does not require full torque below 10 Hz, the Boost (DEC/B) Trimpot can be conserv-
atively 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.
Connect 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.
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.
(Shown Factory Set to 1.5 Volts/Hz)
COMP
0
3
.8
1.5
2.3
FIGURE 31 – SLIP COMPENSATION
TRIMPOT RANGE
(ALL MODELS)
(Shown Factory Set to 5 Volts/Hz)
5
DEC/B
0
30
8
15
23
FIGURE 32 – BOOST TRIMPOT RANGE
(ALL MODELS)
Summary of Contents for SERIES 5
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