Setting the Field Voltage Trim Jumpers
6-1
C
HAPTER
6
Setting the Field Voltage Trim Jumpers
Given a supplied line voltage, field voltage trimming is used to match the drive’s field
output to the rated field voltage of different DC motors.
In general, a field voltage below the motor’s rated field voltage could operate the motor
above rated (base) speed with reduced torque. A field voltage above the motor’s rated
field voltage could result in armature overvoltage and excessive heating in the motor’s
field windings.
Determining the Correct Jumper Setting for Field Voltage Trim
You must set two jumpers to configure field voltage trim. Complete the following steps
to determine the correct jumper setting for the Enhanced Field Supply board and the
Regulator board:
Begin with your AC line input voltage and your motor’s rated DC field voltage.
Step 1. Calculate the line multiplier according to the following formula:
Step 2. Use the resulting line multiplier to set the jumpers as indicated in the
following table:
For example:
AC Line Input Voltage = 230
Motor’s Rated DC Field Voltage = 150
Use jumper setting B–C because the multiplier falls between 0.45 and 0.9.
Table 6.1 – Setting the Enhanced Field Supply Board and the Regulator Board Jumpers
If the line multiplier
falls between:
Set J21 on the Regulator
Board to:
Set the jumper on the
Enhanced Field Supply
Board to:
0.45 to 0.9
B–C
B–C
0.91 to 1.12
A–C
A–C
Motor Rated DC Field Voltage
AC Line Input Voltage
LINE MULTIPLIER =
150
230
0 6528
=
.