LEESON SCR Thyristor Motor Control - Manual (Page 59)

53 Troubleshooting SPEEDMASTER™ OPERATION MANUAL
Symptom Possible
Causes
Suggested
Solutions
Motor pulsates or
surges under load
On non-reversing
drives, motor runs in
the opposite direction
Motor will not stop
when the speed adjust
potentiometer or
reference signal is set
to zero speed.
1. IR COMP is set too high.
2. Control is in current
limit mode.
1. Motor armature leads
are reversed.
1. MIN SPD trimpot is not
adjusted properly.
1. Adjust the IR COMP
setting slightly CCW
until the motor speed
stabilizes (page 38).
2. Check that motor is of
sufficient horsepower
and amperage.
1. Reverse connections to
the motor armature.
1. Slowly rotate the MIN
SPD trimpot until the
motor stops.