VFD Maintenance. Does it work? How often?

[JaxGTO]

Customer was complaining that a VFD we put in 10 years ago was shutting down. Showed customer picture and let him know his Preventive Maintenance plan is not working.


So how often do you have maintenance go check things like this?


Do you give them enough time to do it?


Do you keep paperwork?


Just curious what others are doing. Thanks, Jack.

 

[blftech]

All I can say is, WOW.

 

[rupej]

I would say most people I run into do zero maintenance on small drives- run to failure. On high horsepower (1000+) people seem to take things a lot more seriously due to the downtime involved if one fails.

 

[thingstodo]

drive maintenance

Customer was complaining that a VFD we put in 10 years ago was shutting down. Showed customer picture and let him know his Preventive Maintenance plan is not working.


So how often do you have maintenance go check things like this?


Do you give them enough time to do it?


Do you keep paperwork?


Just curious what others are doing. Thanks, Jack.

We have a PM that our shift electricians do every week to change out the air filters on the drives if they are dirty. No records of that. The air filters are on drives 75 HP and larger.

We have a Preventive Maintenance work order generated once a year, one work order per MCC room. All of the VFDs are listed, originally from most important to least (revisions sometimes don't show in the correct order)

PM is to vacuum/dust the electronics, tighten lugs in the cabinet, tighten terminal blocks. If we are short of time, we sometimes get the vendor to send out a tech to do the cleaning and tightening for MCC rooms where there is only one vendor for the drives. Records kept for the cleaning and whether all drives are completed. If some are skipped due to time, they are lower priority or can be completed on a one-day maintenance down day. They *SHOULD* get transferred to a higher priority work order ... but that seems to slide

The PM is not completed until all of the drives are done. In theory.

1 - yearly
2 - we intend to, and hopefully it's long enough, but not for sure
3 - yes, paperwork kept

 

[jraef]

The VFD service manual I just looked at says filters should be replaced or cleaned every 3 months maximum, sooner depending on the environment.


I once had a customer wanting me to figure out a way to replace the steel structure elements of his MCCs because they were rusting. They had installed NEMA 1 MCCs in a wash-down environment. I don't know how they managed to not kill someone, but one funny thing I found was when I opened one of the VFD compartments, there was fungus growing on the VFDs! You can't make it out here, but these are tiny little mushrooms all over this...

The drives were all still working though!