Rapping sound associated with power

[Miltp920]

This weekend we were at a campground hooked up to 30 amp. I believe their power post had a bad source of power. My wife heard a rapping sound from the vicinity of the inside fuse-breaker panel a couple of times. She heard it before and thought I was digging around in the basement. I heard it myself once, and I thought someone was rapping on the door. This was followed by a loss of power/lights flicker to the camper. Once the power came back on, and I thought unstable power source. We have had to swap outside 30 amp plug in positions in this campground before, last year. The second time when I heard the rapping, the power did not come back on. I went out to the campground breaker and there were no lights on my power surge protector. So I plugged into the other side of the power post for the site next to us, and power came back on to our 5er. No problems for the next two days. We have a 3100, and I think the inverter might be at the bottom of the access doors just inside the main doorway by the inside fuse-breaker panel. My bride thought it might be the inverter. We had one of those fail on our SOB. On SOB, the inverter was under the steps leading up to bedroom. Anyone ever have an issue like this? We do have an appointment at the dealer we bought from in a week. I plan to ask them to check out this area / power / inverter. I am concerned about this rapping sound and future failure of something.

 

[osims]

It is probably your transfer switch, that switches from shore power to generator. They will chatter with low voltage.

 

[cookie]

You mentioned a surge protector, is this a Progressive Industries unit that will tell you what went wrong?
Sounds like it could be overcurrent, which will not be dealt with on every surge protector. Possibly your unit.
If it were me and I had a power problem at a particular campground more than once, there would never be a chance that it would happen a third time.
You also mentioned that your inverter (converter?) failed on your SOB. Did you camp at this same campground with it as well?
Overcurrent will kill a lot of electrical devices.
Oh, did you happen to use your VOM and check the voltage at the pedestal?
Be sure to let us know what you find out.

Peace
Dave

 

[danemayer]

Your transfer switch looks for 105 volts on L1 in order to activate the contactors. If power drops below 105 V, the contactors will drop and you lose power to the coach. A rapping/clunking noise may be a momentary drop that causes the contactors to cycle partially, and cause 110V devices to flicker. If your battery is low, when the power drops momentarily, the Power Converter (which also looks for 105 Volts to provide output) will stop providing 12V DC to your 12V lights and other devices. If the battery is low when power drops, the lights may flicker.

If you're using an adapter from 30 amp to 50 amp, don't overlook the possibility that you have a marginal adapter.

Repeated power drops and contactor cycling under load may cause pitting of the contacts, leading to additional problems down the road. You should get to the bottom of this.

 

[MTPockets]

If you have a generator, I would suspect the transfer switch. Ours did that at a park and it stopped when we plugged into another pole. We were warned on the forum our transfer switch contacts may have been damaged. We had no problems while traveling the next three months, but the switch did go bad one day. We ordered new switch like old one we found on Amazon.com and installed in 30 minutes. No problem since.

 

[Miltp920]

(If it were me and I had a power problem at a particular campground more than once, there would never be a chance that it would happen a third time.)

Well, we go to this park to see some very good friends. That is the reason for the repeat visits. There is clearly neglect in the upkeep of this campground. We may need to start visiting without staying over night with the RV. We do have a generator. Sounds like you have helped me identify the problem. I do use a 30 amp to 50 amp jumper. I may need to upgrade to a new one. It sounds like the 105 line voltage dropped on incoming, and caused the chatter in the transfer switch. That makes sense. Not sure why the park pedistal went dead, but switching to the next sites power restored us for our stay. I will ask the dealer to look at the transfer switch, and maybe pick one up in anticipation of failure.

(You also mentioned that your inverter (converter?) failed on your SOB. Did you camp at this same campground with it as well?) We never camped at this campground with that SOB. It failed as a NEW unit before we even camped in it. Warranty replaced it.

 

[Miltp920]

(If the battery is low when power drops, the lights may flicker.)

I trickle charged the battery before season installation. I assume that the battery is constantly being charged while installed by shore power?

 

[Miltp920]

Well, I took it to the dealer today, and I told them about what we heard "rapping". They said the transfer switch for the generator should not cycle unless the generator is running. They took the bottom power "box" out (just inside the door by the floor). The back side of this box had the white wires going to the hot water heater (labeled with sharpie) and other loads. The said my inverter-converter is mounted on the basement side of the wall right next to this power box. The tech said he had to tighten one of the 110 wires on this converter-inverter. He checked the DC coming from the inverter-converter at the disconnected battery to find the right DC voltage (I think it was 13 volts). So, I am hoping that we will not hear anymore rapping sounds. AND we may just NOT go back to that run down campground with the 5er. Thanks to all who responded to help me understand my issue.