Home Forums General Discussion Print Talk Garaventa Elvoron Power board schematic question

I have a Garaventa Elvoron that is giving me some grief. I have the Electrical Schematic for the Elvoron MRL power board connections. I have been studying it to see if I can get a better idea of what is happening here, but I have an unidentified component that I am hoping someone can tell me what it is.
At the top of the page, to the right of T1, there is an unidentified rectangular symbol connected across L1 and L2. From the top of this symbol there is a line labeled "48VDC" that connects to pin 8 of PF relay. Pin 1 of PF connects to Pin 8 of PF1 relay and Pin 1 of PF1 connects to Line 2. Is this symbol for a 48 VDC power supply that connects the two relays in series with presumably 24 volt coils? If the connection to PF is positive, would the negative conductor be connected to L2 internally? I find this a bit odd.

Did you ever get a reply to your problem. Just saw this and I've been through that powerboard a bunch of times

Hi Ron,
Nothing yet. I sent you a PM

I believe it is a "power supply" that feeds those 2 power relays. They don't utilize a typical power supply since its only drives low current relays so its made with capacitor/resistor and zener (I think). Ive had issue with the circuit getting weak where it doesn't pick one or both of the 24VDC PF relays. Pulling one out slightly and then pushing it back in after a power on was a temp fix. I haven't looked to much into detail before since the customer didn't want further troubleshooting done. The board isn't fun to remove/replace either!

I've done some more research into what I think that circuit is and I agree with you on that. I'm an electrician, not an electronics engineer, but if that mains dropping capacitor is getting weak, perhaps the breaking of the coils circuit momentarily induces enough voltage to get it over the minimum pull in voltage required. Just an semi-educated guess.

From what I can see, the board is quite simple and should be repairable, but it wouldn't be fun to re an re for sure. Garaventa told me it is not repairable and has to be replaced (for ~$3000.00 CDN). When I asked them why it failed they told me that it was an over voltage on the supply side. This was without removing the board or testing anything. When I requested more information from them they have chosen not to return my calls or e-mails.

I smell a rat. My measured voltage is and was 122/244V, well within our utilities acceptable limits. If indeed the board was damaged with this incoming voltage then there is something wrong with the design.

I have been using the trick of pulling one of the PF relays and replacing it to get things going again, but I'm afraid that sooner or later this might not work any more. The sockets of the relay socket might lose their tension, or I might break a relay pin off. We don't often get long outages, but we get a fair number of short ones, less than a few minutes or more often, just enough to blink the lights. Probably caused by a recloser operating if a branch or something shorts the high voltage lines.

Other than this fail to reset after a power outage, the elevator seems to function satisfactorily. Having said that, I don't think the emergency lowering function was ever tested on commissioning, there certainly is no record of that. The little UPS seems to be functioning but the lowering function doesn't work when I tried it. I do have some of the electrical drawings and the installation guide that I had to make sure the shaft was the right dimension. They left no operating manual, troubleshooting guide, or even a list of the trouble codes.

One way to get around this fail to reset would be to install a double conversion UPS on the supply side. This would ensure that the controller would never see an outage and the incoming voltage would be as regulated and pure as you could get. That is, assuming there is enough battery capacity to keep things alive for a reasonable length of time.

Another work around I am considering would be to just remove PF and PF1 and just jumper the N.O. contacts. There would be no emergency lowering with the existing little UPS of course, but it doesn't work anyway. With the jumpers in place everything should come back to life on restoration of power, unless there is something else wrong with the board.

Anyway, these are my thoughts at present.

You should not "add" a power supply to keep it on during a power outage. You should also not remove a relay and replace it with jumpers. Both of those things can be very dangerous to the next person to work on the elevator or even you if there's an emergency and you forget. Im not familiar with garaventa but other residential elevators but I have worked on other residential elevators and if the power supply is weak or damaged you can get similar issues. Start with replacing the power supply. Other residential elevators use power supplies that take 240vac and turn it to 24vdc so you could go that route. You could also check your power supply output (the DC side) on a with your meter. You should have less then 10 milli volts of ac ripple

I've got a dead powerboard on the shelf here. The local Garavanta guy told me if I could repair it, he'd get me more to fix. I've not been too incentived to work on it, but I there is a PLA chip on the thing that is likely fried which kind of puts me at a dead end (not willing to hack my good board to figure it out). The rest of it is pretty straightforward from the prints.

If I had a dead board at my disposal, the first thing I would check would be the mains dropping capacitor power supply to PF and PF1. It is just a basic circuit that takes 240VAC and drops it to 48VDC. All through hole components and should be easy to check and replace. I base this on what symptoms my board is showing, yours may be entirely different of course.