Ovfr1a 404 drive

Hello everyone. First post and glad to be part of the group. I worked for otis most of my career and recently was hired by thyssenkrupp in December to take over route with mostly otis equipment. Im having an intermittent issue with a drive on a gcs mrl with a ovfr1a-404 drive. When I show up to the call the car is either in service with a drive fault logged or shut down in mcss on a drive fault. Always resets and runs immediately and runs for weeks. When I plug into the drive I'm seeing vac under fault and vac in balance. There's also a buss cap fail and pll unlock fault sometimes. Every once in a while I'll have an encoder feedback fault also but my encoder feedback seems perfect as I'm running the car and watching. So now that I've gotten that out of the way I am trying to tell the customer that I believe there is building power issues going on in the building. I plugged into the drive in the car at the other end of the building and the first three faults that popped up were all related to low vac. Any thoughts? I replaced the encoder because it was cheap and easy and we sent the drive out (even though I didn't want to) to be rebuilt. This customer is the federal government and are very difficult to deal with or I would have never sent the drive out.

Forgot to add that main line voltage is always perfect when I meter it and ive suspected there to be an incoming power issue all along but the government forced my hand to "fix something" even though I didn't believeit was ever an elevator issue.

This is actually kind of common with Otis drives in my experience. Mostly with OVF30 and 40 though. They seem to start getting low lin, buss undervolt and PLL unlock faults. I had gone around with the building about incoming power etc. and finally sent the drive to ITS and it’s fixed. It may be an elevator issue. If you really suspect building power you need to hook up a 3 phase voltage monitor, your shop should have one.

We sent the drive to access and they said they found a bad capacitor. The customer has a monitor hooked up now recording data. I put the elevator on random car calls every 90 seconds for nine days and couldn't get the car to shut down. When I say this happens intermittent, I'd say once every 3 weeks. I agree with you on this being a common thing with the ovf drives. Problem I have is in my experience a drive issue isn't this intermittent. Especially as much as I ran that car testing it. Thanks for your reply.

So you got the drive back and the problem persists? You said you work for TK, why didn’t they send it to ITS? Do they not work on the newer drives?

I've worked for tke for three months. I was told ITS doesnt support that drive. Its very very intermittent. So yes the problem still persists. Very strange. Im not a rookie with these drives and I wouldn't call myself an expert either. In my experience when the drive is telling you that it sees low vac that it pretty accurate unless I'm missing something here?

I will also add that we've went drives to access control and gotten them back in the same condition we've sent them. They seem to be about 50/50.

Just a thought, are they perhaps running a monthly building generator test? Or perhaps there is something else on the same line voltage as the elevators. Every three weeks seems too intermittent for an elevator issue.

John thanks for your reply.... So this whole complex is "off the grid as far as power goes. They make there own generator power all the time. Very secure area. They have lots of power issues on site but I believe its only showing itself in this particular building because the rest of the complex has hydro's and when they shut down because of power its always a low oil switch tripped. They are also very secretive about power issues. I usually find out about them inadvertently. Maybe they dont want to me billed. Who knows?

You need to put your own voltage monitor on the car. The next time it happens you can compare the time the fault occurred to the recorded data and you will know if the problem is with the building power. After this off the grid info I’m sure you’re on the right track. There could be large motors in the building or some other current draw that pulls down the voltage when enough of them start at the same time.

We are in the process of doing this. Im kind of glad you folks are kind of running the same ideas through your head that I have.

Does this controller have a regen unit on it? Is this a pm ac machine? I'm not familiar with Otis model that's why I asked those simple questions. I had a similar problem with a Mce Ibox pm ac machine recently. Our issue turned out to be with the regen unit and computation choke bit we were traveling the same path you are.

It is a regen drive but a DC motor.

Otis is using DC motors on their MRLs? I did not know that, haven’t seen one. Is it brushless?

Ovfr40 is an A/C drive

Have you looked at your brake circuit and relays to see if you relays were working and you had the correct voltages? Also check the rectifier in the brake circuit for the correct voltages.