25
13.8 Boost (BOOST) –
The drive is factory set for Fixed Boost
(Jumper J6 set to the “FIX” position). When the drive is
set for Adjustable Boost (Jumper J6 set to the “ADJ”
position), the BOOST Trimpot can be used to adjust the
amount of boost voltage to the motor. See Figure 37. Also
see Section 6.5 on page 18.
Application Note –
The Boost function operates over
a frequency range of 0 – 15 Hz. If the frequency range
required is above 15 Hz, Boost adjustment is not
necessary.
WARNING! To avoid motor winding overheating and failure, do not overboost the motor.
Note:
An unloaded motor with excessive boost will draw more current than a partially
loaded motor.
The boost voltage 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).
3.
Increase the boost until the ammeter reaches the motor nameplate rated current
(Amps AC).
4.
Using the Main Speed Potentiometer, slowly adjust the motor speed over a 1 – 15 Hz
(0 – 450 RPM) range. If the motor current exceeds the nameplate rating, decrease the
boost setting.
Trip T
ime
(Minutes)
CL (Factory Setting)
140
110
120
130
0.1
Motor Current (%)
1
160
150
10
100
1000
Figure 36 – I
2
t Trip Time vs. Motor Current
BOOST
(Shown Factory Set to 5 Volts/Hz)
5
0
8
30
22
15
Figure 37 – Boost
Trimpot Range