Application Note –
On applications with high inertial loads,
the deceleration may automatically increase in time. This will
slow down the rate of speed of decrease to prevent the bus
voltage from rising to the Overvoltage Trip point. This function
is called Regeneration Protection.
It is recommended that
for very high inertial loads that both the ACC and DEC/B
Trimpots should be set to greater than 10 seconds.
13.5 Slip Compensation (COMP) –
Sets the amount of Volts/Hz
to maintain set motor speed under varying loads. The
COMP Trimpot is factory set to 1.5 Volts/Hz, which pro-
vides excellent speed regulation for most motors. To
increase the slip compensation, rotate the COMP Trimpot
clockwise. To decrease the slip compensation, rotate the
COMP Trimpot counterclockwise. See Figure 26.
The slip compensation may be adjusted as follows:
1.
Wire 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 (Amps AC).
40
17
3
(Shown Factory Set to 1.5 Seconds)
Seconds
.3
1.5
20
10
FIGURE 25 – DECELERATION
TRIMPOT (DEC/B) RANGE
2.3
.8
(Shown Factory Set to 1.5 Volts/Hz)
Volts/Hz
0
3
1.5
FIGURE 26 – SLIP COMPENSATION
TRIMPOT (COMP) RANGE
(Shown Factory Set to 5 Volts/Hz)
5
Volts/Hz
0
30
8
15
23
FIGURE 27 – BOOST
TRIMPOT (DEC/B) RANGE
