Rockwell Automation DC3R Regenerative DC Drive User Guide 1/4 - 2 HP, 115/230 VAC - Manual (Page 48)

40 Troubleshooting
Line fuse blows
1. Disconnect AC line voltage from the drive.
2. Check that the motor cable and armature is not shorted or grounded.
a. Armature resistance should measure approximately 1 to 100 ohms,
depending on motor horsepower.
b. A resistance reading from the motor frame to either armature side
should show open when an ohmmeter is used on its high resistance
scale.
3. Check that the field circuit is not open.
4. A combination of ambient conditions and frequent
high-current spikes (i.e. reversing) causes fuse to “nuisance trip”.
Consider using a slow-blow fuse, or over-rating the fuse 120%
Motor pulsates or surges under load
Readjust the IR COMP setting slightly CCW until the motor speed is
stabilized.
Line fuse does not blow, but the motor does not run
1. Verify that the speed adjust potentiometer is not set to its zero speed
position.
2. Check the speed adjust potentiometer for continuity.
3. Verify that the inhibit pins are not shorted together.
4. Check that INHIBIT–RUN terminals 2 and 3 are connected.
5. Verify that the drive is receiving AC line voltage.
6. Check that the drive is not in current limit. If the drive is in current
limit, verify that the motor is not jammed. It may be necessary to
increase the FWD TQ or REV TQ setting if it is set lower than the
current rating of the motor.
7. Check that the speed adjust potentiometer connections to the terminal
block are correct and not open.
Motor runs too fast at the maximum speed setting
1. Check that the MIN SPD and MAX SPD setting is not set too high.
2. Check that the field output connections are secure if you are using a
shunt wound motor.