Per the IEEE, the failure rate is 3 times higher for electrical systems that are not subjected to a regular PM program. Since medium voltage variable frequency drives (VFD) not only have high costs, but are difficult to readily replace, a medium voltage VFD PM program makes a lot of economic sense.
What causes failures in electrical systems? Loose connections and moisture are responsible for almost half of failures. Where medium voltage VFDs are concerned, those failures can be expensive, and in many cases disastrous.
Medium Voltage variable frequency drive (VFD) preventive maintenance (PM) generally involves the following:
- Visual, thermographic, or other non-invasive inspections prior to shutdown
- All circuit breakers/disconnects repeatedly opened and closed to insure proper operation
- Protective Relays and Devices tested and calibrated
- Test oil samples from all oil filled equipment (transformers)
- Electronic equipment inspected, cleaned, and tuned
A major preventive and predictive maintenance consideration for medium voltage variable frequency drives (VFD) is bus capacitors.
Per most manufacturers, bus capacitors have a life span of 7 years. That time can be affected by voltage levels and temperature. Higher voltages shorten the life, as do higher temps. (Click HERE for more information on bus cap failures)
Another overlooked item in predictive maintenance on medium voltage variable frequency drives (VFD) is cooling fans. It is an easy item, along with filters, to overlook. Higher temps will shorten the life of a number of drive components.
As we often tell our customers,
- Keep it clean
- Keep it cool
- and Keep our competitors away from it
If you’d like to discuss PM on your medium voltage VFDs, hit any of the contact methods on the right of this page, or call 770-448-4644.
No One, Anywhere, is Better at Drives than we are.