Allen Bradley DC Drive/Locked Rotor
Hi
Can anyone advise me please. I have an Allen Bradley 1397 regenerative DC drive operating a 100 kW DC motor for movement of a gantry crane. When the drive is told to move the crane to the left, I get an armature current of about 45A. However when the drive is told to move the crane to the right, I have no motor rotation and high armature current (in limit). These figures are with the motor uncoupled which was done to rule out a mechanical/gearbox problem. With the drive assigned to move right but no speed reference given, the motor is locked solid, the only power going to the motor is 2.88A field current. On a direction change command to the left, field current stays the same but again with no speed reference, the rotor is fairly free to rotate. If I swap round the armature cables, the fault then transfers to the other direction of rotation, i.e locked rotor with only field current on. I've checked armature current feedback which shows all thyristors conducting normally, all parameters are as per original commissioning and have swapped each board in the drive with our spare, one board at a time. Each time the fault stays the same. Field and armature connections have been checked, meggered etc with no problems found (2 Field windings each 75 Ohm connected in parallel) Any suggestions please would be most welcome.
Thanks everybody!
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Linear Mode
