Industrial drive repair is an important discussion point in most manufacturing facilities. Often, the discussion is whether it’s worth repairing a VFD. Or just buy a new one.
VFDs (Variable Frequency Drives) have decreased in price over the years. And with standard VFDs, it’s often economical to replace rather than repair the VFD. A reputable VFD repair company will tell you up front when a drive just isn’t worth repairing.
Many VFDs ARE worthy of repair. Here are some examples where repairing and AC drive might be preferable to replacing it.
When Industrial Drive Repair Makes Sense
It’s a specialized VFD. Some plants have machines worth millions of dollars that have small, very specialized VFDs. Due to communication bus issues, spacing issues (or other application specific reasons) it’s just not feasible to replace them. Innovative-IDM and other reputable repair depots can repair these specialized VFDs and keep the machine running.
It’s a large horsepower unit. The larger the HP, the more likely it is that repairing the VFD is a better option than replacement. For one thing, the installation costs alone on a large HP VFD can be significant, often exceeding the repair costs. We see significant numbers of high horsepower VFD repairs at our repair shop.
Servos. Servo drives are, in general, expensive. They also tend to have application specific software and communication protocols and are often great candidates for repair.
There are large numbers of the specific VFD in the facility. Once you have spares, your maintenance personnel have experience on the units. Now you can use a drive repair company for backup; it might make more sense to stay with what you have and just repair the VFD s rather than replace with new.
We have many customers in this situation. They weigh the cost of the VFD repair, against the TOTAL cost of replacement, which includes things like spares, personnel training, etc.
So, what goes wrong with VFDs?
In general, VFDs are quite reliable. But like any piece of machinery, they have common break points that cause problems, such as:
Loose connections. Don’t laugh, it’s a major cause of VFD downtime. Check simple stuff first. Is a plug on the main circuit board loose? Check your connections before trying a more complex VFD repair.
Cooling Fans. Major cause of problems in industrial drive repair. Some VFD s will let you know about this, but most won’t until you begin tripping on over temperature. The overheating can, and almost certainly will, cause major issues long term. Check your fans often.
Electrolytic Capacitors. These have relatively short lives compared to other components. Overheating shortens it even more.
Power Semiconductors. These are less common, but drastic failures. If this happens, do NOT just replace the IGBT or Diode, find out why if failed. Or, you’ll likely just be replacing it again as soon as you power up.
VFD Software or programming. Was it running before you tried changing a parameter? Then put it all back to where it was and see if that fixes it. Don’t automatically install factory suggested software revisions until you back up what’s running. In general, if it’s running fine now, leave the programming alone.
Circuit boards. These are much less common industrial drive repair failure than one might think, but is often the first thing suspected when an inexperienced technician begins to repair a VFD.
We give firm VFD repair quotes at IIDM and provide free evaluations in our shop. Email me and I’d be happy to discuss your individual situation, or pass you along to one of our technicians for further discussion about whether it’s worth repairing your variable frequency drive, or replacing it with a new one. BTW, did you know that IDM stands for Industrial Drive Maintenance? Isn’t that the kind of repair company you want for your industrial drive repairs?
Marc Phelps is manager of the Innovative-IDM repair facility in Houston. You can contact him at email@example.com