Garage Door Opener Electrical Problem

You need to find out what it was that died on the two broken boards.

Typically, the drive motor is switched using a relay or small contactor, and it is this that I would check first - IMHO this is what has most probably failed.

The scenario that springs to mind is that the voltage dips, the motor draws more current to compensate, the contacts in the relay/contactor fry up, and the unit ceases to function. Bearing in mind that the manufacturer will have used a relay that operates as close to it's maximum rating as is economically possible under more normal supply conditions, it is not hard to see how this failure could occur.

If I am right, the solution is to replace the relay with one with a higher contact rating and the problem will go away.

You have a power quality problem. The warning about spikes are quite real. It occurs whenever load is switched on the generator. After all it is a big inductor. When it drops off, and the inverter picks up, that is not a seamless transition. You get spikes then too.

Then there is an unrelated problem. The generator puts out a nice sinus waveform. Inverters put out square wave instead. Many electronic devices cannot take that. Plain old power supplies (what you most likely have there) produce much higher, than normal DC voltages, easily frying internal components. The driving motor could not care less.

There are two choices. Somebody, who really knows what he is doing disconnects the power supply section on the board, and converts it to a battery supplied one. The other one is a ferroresonant transformer (CVT). With its resonant circuit it is keeping the voltage nice and stable, gives you clean sinus wave, and swallows spikes. Any good electrical supply house has it. Do not forget to include the motors power demand, when selecting size. Sola is the maker I mostly used.

Thank you for your prompt replies. I believe that "Del the cat" hit it on the nose, "mass produced rubbish". Still, I have what I have, and short of starting over I would like to fix what I have if I can. I agree with most of what you are saying except for one of the four times the boards were destroyed the motor was not running. The door openers have power to them at all times so they can receive a wireless signal to activate. It is during this idle time that three of the boards destroyed, so it is probably in the power supply section of the board. "Leveles" is correct in that it is a "power quality problem", but why does it only effect this piece of equipment? I know, it's a piece of rubbish! After the first boards destroyed I added the surge protector in hopes that that would take care of the problem. I don't know if it isn't sensitive enough or it's another problem. Guess I'll have to pull the boards and see if the problem can be located. Maybe I can convert the control section of the board to run on DC and keep the AC for the motor and light. The problem I see in using a CVT is the constant power draw that a transformer has even when there isn't a load on it. I am "Off Grid" and power consumption is a major concern. In reference to "Leveles" comment on the power supply: The pair of OutBack VFX3524s is a sophisticated sin-wave 120/240 VAC inverter package capable of 7000 watts.

Put it on a UPS (Uninterruptable Power Supply) and your problems will go away.

Make sure the UPS is large enough to carry the door opener motor ampacity load.

If you cannot find a used UPS and the cost is prohibitive, you might get away with installing a "one to one" transfomer between the door opener and the power outlet.

Or; you might be able to install an Inductor + Capacitor network on the opener power side that could filter the "bumps" out of the generator power. Size of the components would be determined by identifying the frequencies of the disruptions needing to be filtered.

You can play with the garage door system and more then likely make it work. But... you are only masking the true problem. The true problem as I see it, is the way in which your generator and inverter are configured.

It sounds like the generator also supplies AC power to your loads while it is running. You need to rethink this and remove the loads from the generator and leave them on the inverter all of the time. In that way, you will no longer see transition spikes on your AC loads from the generator starting and stopping. The problem is more then likely due to the inverter and generator not being in phase with each other at change over. The out of phase condition can dump some pretty high voltage levels into your system. Surge suppressors may not provide the protection needed in such an event, as the let through voltage for a 120 volt device, as per the UL standard is, off the top of my head, over 300 volts.

Given the configuration you mentioned, you are bound to have problems with other electronic equipment. If the inverter is a true sine wave unit, changing the setup so the generator only charges the batteries will solve the majority of your problems.

I don't think that the voltage drop would be where your problem is occurring. As others have stated, you must be seeing a spike somewhere in your system, or ripple is being induced in your power supply due to internal or external influences. Some power supplies are extremely sensitive to AC ripple.

I briefly looked at a cut-sheet for the TDX. This is only a surge suppressor. I don't see a mention of the frequency limits for the transient suppression section, though I would suspect it should cover the gamut.

Could you post a rough schematic of your layout? Please try to remember the size restrictions on CR4 make some pix difficult to interpret.

Additionally, if you have a ground wire from the outside of the circuit, that is another way to get spikes in.

The spike suppressor can be good quality. But, to block every possibility it needs 3 MOV per plug: Hot-N, H-G, N-G to cover every eventuality. 110VACeffective is = 154VACpeak. To minimise leak, normally 250V or 300V clamping voltage MOVs were installed. Your board may not be able to take that. It should, but that is different. In your system you may try replace them with 200 - 230V types.

THe pushbuttons are normally connected by phone wires. Mine was, and it regularly activated, when a police cruiser turned on its radio. (a few watts) Opening the cover up, the place for a blocking capacitor (10nF or so) was there, with no capacitor, most likely a production wiseguy saving 10 cents. A lightning induced spike can do a number on this input. Healthy voltage there is about 0.5VDC there.

The last one is simple. Take off the cover. I have seen too many electronics failing due overheating.

I'd be interested in knowing if this just started happening or if you just recently installed the door opening system? If this is a newly installed system, did you make sure the counter-balance springs are adjusted properly to compensate for the door's weight? Being the C/B is the weakest link in the system, the motor may be frying the board while trying to lift more weight than what the motor is capable of, without the spring assistance. Just my 2¢ worth, DJ