ASD SERIES INSTALLATION AND OPERATION MANUAL
17
12
–
TRIMPOT ADJUSTMENTS
The drive contains trimpots which are factory set for most applications. See Figures 4
– 6 on pages 8 – 10 for the
location of the trimpots and their approximate factory calibrated positions. Some applications may require
readjustment of the trimpots in order to tailor the drive for a specific requirement. The trimpots may be readjusted as
described in this section.
WARNING!
If possible, do not adjust trimpots with the main power applied. If adjustments are made with the
main power applied, an insulated adjustment tool must be used and safety glasses must be worn. High voltage
exists in this drive. Fire and/or electrocution can result if caution is not exercised. The Safety Warnings on page 5
must be read and understood before proceeding.
12.1
– MINIMUM SPEED TRIMPOT (MIN)
Sets the minimum speed of the motor. The MIN Trimpot is factory set to 0% of frequency setting. For a higher
minimum speed setting, rotate the MIN Trimpot clockwise. See Figure 24.
12.2
– MAXIMUM SPEED TRIMPOT (MAX)
Sets the maximum speed of the motor. The MAX Trimpot is factory set to 100% of frequency setting. For a lower
maximum speed setting, rotate the MAX Trimpot counterclockwise. For a higher maximum speed setting, rotate the
MAX Trimpot clockwise. See Figure 25.
12.3
– ACCELERATION TRIMPOT (ACCEL)
Sets the amount of time for the motor to accelerate from zero speed to full speed. The ACCEL Trimpot is factory set
to 1.5 seconds. For longer acceleration time, rotate the ACCEL Trimpot clockwise. For more rapid acceleration,
rotate the ACCEL Trimpot counterclockwise. See Figure 26.
Note:
Rapid acceleration settings may cause the current limit circuit to activate, which will extend the acceleration
time.
12.4
– DECELERATION TRIMPOT (DECEL)
Sets the amount of time for the motor to decelerate from full speed to zero speed. The DECEL Trimpot is factory set
to 1.5 seconds. For longer deceleration time, rotate the DECEL Trimpot clockwise. For more rapid deceleration,
rotate the DECEL Trimpot counterclockwise. See Figure 27.
Application Note:
On applications with high inertial loads, the deceleration time may automatically increase. This
will slow down the decrease speed 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 ACCEL and
DECEL Trimpots be set to greater than 10 seconds.
12.5
– DC INJECTION BRAKE TRIMPOT (DECEL)
The drive is factory set for Regenerative Braking (Jumper J7 set to the "RG" position). When the drive is set for DC
Injection Brake (Jumper J7 set to the "INJ" position), the DECEL Trimpot is used to set the amount of time the DC
current is applied to the motor. See Figure 28. Also see Section 10.6 on page 16.
12.6
– SLIP COMPENSATION TRIMPOT (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 provides 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 29.
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 (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 constant speed under varying loads.
12.7
– MOTOR OVERLOAD (I
2
t) WITH RMS CURRENT LIMIT TRIMPOT (CL)
UL approved as an electronic overload protector for motors. Sets the current limit (overload),
which limits the maximum current to the motor, which prevents motor burnout and eliminates
nuisance trips. The CL Trimpot is factory set to 160% of the drive rated current. To increase the
current limit, rotate the CL Trimpot clockwise. To decrease the Current limit, rotate the CL
Trimpot counterclockwise. See Figure 30. Also see Figure 31 on page 18.
The current limit may be adjusted as follows:
1.
Connect an AC RMS ammeter in series with one motor phase.
2.
Set the CL Trimpot fully counterclockwise.
3.
Adjust the speed setting to 30%.
4.
Lock the motor shaft and adjust the CL Trimpot to 160% of the motor rated current.
Note: This adjustment must be made within 6 seconds or an I
2
t Trip will occur.
FIGURE 24
MINIMIM SPEED
TRIMPOT RANGE
FIGURE 25
MAXIMUM SPEED
TRIMPOT RANGE
FIGURE 26
ACCELERATION
TRIMPOT RANGE
FIGURE 27
DECELERATION
TRIMPOT RANGE
FIGURE 28
DC INJECTION BRAKE
TRIMPOT RANGE
FIGURE 29
SLIP COMPENSATION
TRIMPOT RANGE
FIGURE 30
CURRENT LIMIT
TRIMPOT RANGE
FIGURE 31
I
2
t TRIP TIME VS. MOTOR CURRENT
