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Moog DBS Drive Repairs

EMA routinely repairs the Moog DBS drive. The following is a short over-view of that process, performed in EMA’s Cortland, NY facility.

Once a Moog DBS drive is received for repair, an evaluation is performed on the unit. The evaluation is to determine the extent of damage to the Moog DBS Moog DPS Drive Control Boarddrive. It is rare, (it’s happened once) for a Moog DBS drive to be deemed beyond repair. In the one case, the Moog DBS drive had severe corrosion on both the circuit boards and power modules. Following the evaluation, a repair quote is generated.

After approval, EMA begins a further analysis of the Moog DBS drive to determine exactly which parts will be needed. Every individual component on the Power Interface board is measured or tested to verify it is working and is within specs. The power modules (IGBTs, SCRs, Diodes) are tested as well, and replaced as needed.

The DC Bus capacitors have been a major issue. (See Electrolytic Capacitors: The Ticking Time Bomb) Sometimes the Moog DBS drive arrives with obviouslyMoog Capacitor damaged DC Bus Capacitors, and at other times, they have failed during load testing. ( This is a photo of a failed DC Bus capacitor from a recent repair.)

EMA replaces EVERY capacitor with a higher grade substitute. Besides the capacitors failing violently and making a loud noise the main problem with this failure is they could take out the control board in the process by throwing carbon or shrapnel at the control board in close proximity of the DC bus capacitors.

EMA installs a dielectric protector cover on the control board to help save the control board. This is especially beneficial since the control board contains proprietary software integrated circuits. The control board itself has been extremely hard to obtain.

Once the Moog DBS drive has been completely repaired, it is taken to the load testing center built at EMA. Each drive is put through full load testing to aggravate any further hidden damage not found during bench testing. This is where the DC bus capacitor weaknesses were found on more than one occasion. Load testing has saved several Moog DBS drive repairs from leaving with further hidden problems.

EMA now stocks a full line of parts to repair the Moog DBS E75, the Moog DBS E50, and Moog DBS E25 models to reduce the repair turnaround time. Call EMA’s Cortland facility at 607-756-0424 or hit any of the contact methods on the right of this page.

No-One, Anywhere is Better at Drives than We are.. (and that includes Moog DBS drives)


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