Allen Bradley VFD Failure: Can It Be Repaired? – A Plant Floor Case Study

REPAIR SOLUTIONS FROM THE PLANT FLOOR – Allen Bradley VFD Blown! Can it be Repaired?  Should it be repaired?

Unlike in a box of Cracker Jacks, there was an UGLY surprise waiting inside of this drive! When this Allen Bradley VFD failed, the screen gave only a wimpy “bad fuse” alarm. But it was much uglier than that for our Western U.S. power generation customer.

When removing the board assembly over the IGBT modules we discovered that the 3 phase bridge rectifier was badly blown. In simple terms, a bridge rectifier converts AC voltage into DC voltage. In addition, the high voltage bus capacitors were bad, three output IGBT modules needed replacing, the film capacitors and MOV’s in the A/C input circuit needed cleaning, and of course, the nearly unidentifiable blown 3 phase bridge rectifier needed replacing.

What went wrong here?

As in most cases, there could be a number of causes for this problem. The most common causes of damage like this to modern VFDs include over voltages, fault currents, inappropriate programming of operation parameters that exceed the machine’s intended capabilities, and, of course, aging components.

This good quality Allen Bradley VFD was worth repairing. And, at almost 65% less than the cost of new, saved our customer a serious chunk of change. If you are having VFD alarms or failure, we can help!  Most variable frequency drives can, and should, be repaired!

About the Author: ACS Industrial  is an independent industrial electronic repair center providing repair services for drives of all types and most all manufacturers including servo drive repairs, AC/DC drives, VFD drives, servo motors, encoders, printed circuit board repairs, monitors and touchscreens, PLCs, test equipment, light curtains, and much more.  Our customer service team is available to answer your questions and help solve your industrial electronic repair concerns. Legacy equipment can be repaired! RUSH Service is available. You can reach them by calling 800-605-6419