Blown, leaky, or finicky capacitors can be a problem with Indramat and Rexroth drives. Capacitors are an older, more fragile technology that many newer machines have improved on but with older Indramat servo drives, capacitors aren’t an uncommon sight. Capacitors are often little tower-like objects attached to circuit boards.
One of the problems you may encounter when powering up Indramat servo drives after they’ve been idle is a blown capacitor. Capacitors on older equipment, like Indramat servos, need to build up their charge again before being given a full powered jolt back to life. Instead of injecting the Frankenstein of Indramat servo drives with a powerful level of current, Indramat and Rexroth often recommend specific steps of voltage to ensure capacitors build up a charge before being overloaded. If you don’t know the steps to take your Indramat servo drive through when powering on, try checking your manual (or request a manual if you don’t have one).
Another problem with capacitors is that they can sometimes be faulty and leak or break. When this happens, electrolytic solution often leaks out of the capacitor and leaves residue on the board. This can sometimes cause damage to the circuit board and require cleanup and replacement. Other capacitors blow the top and some bits of the layers inside the capacitor start to show. Over time, as Indramat servo drives age, capacitors can reach an age when they become fragile and leak or blow.
Replacing broken capacitors is a solution but know that there are lots of capacitors that are faulty these days. It’s to the point where there are individual businesses that make capacitor replacement their only service. Replacement by the Rexroth factory with Rexroth parts is important to getting the right capacitor soldered correctly to your Indramat servo drive circuit board. Without the right parts and know-how, you could be putting your Indramat legacy drive at risk.
We stick with factory repairs to make sure that everything is done correctly 100% of the time. If you think you might have a busted capacitor on your Indramat servo drive, call us and we can help identify the problem. Be sure, too, to remember that capacitors take 5 minutes or more to discharge, which means you need to wait before touching them after powering down to make sure you don’t fry your Indramat servo drive.