Transfer switch

whmprt · 12-20-2009, 09:09 AM

The transfer switch in my MH buzzes. Is this bad and if so is there anything one can do other than replacing it?

Bill M
03 Contessa

**Gary RVRoamer** · 12-20-2009, 09:45 AM

Does it buzz everywhere you hook-up or only in one place? Sometimes over/under voltage or an AC frequency other than 60Hz can cause them to be noisy.

Otherwise I would expect that it has an internal problem with one of more of its relays. May not fail for a long, long time, though. Someone who is handy electrically could replace the buzzing relay(s). Might be a bit of a chore to identify the relay make & model and locate a source for a replacement, but it is not a difficult job to do once you have the part.

hillbilly3 · 12-20-2009, 10:52 AM

I'm not familar with RV transfer switches, but with regular generator transfer switches, they are mechanically held, in other words electric power is used to transfer the contacts, but once that is done power is removed from the coil via clearing contacts. If these contacts fail or the switch does not fully close, it will cause the "hum". If left uncorrected, it will destroy the coil. Another possibility may be that it is electrically held, in which electricity holds the contacts closed. If it is this type, then there is debris or corrosion on the face of the laminations. This will cause a hum that will get louder or quieter every time it is transfered.

**"007"** · 12-20-2009, 11:14 AM

With all the power off and if your comfortable working on electrical apparatus, take off cover of TS and check for foreign matter,metal filings or dirt in between relay magnet and post and clean out. Also you can run a dollar bill thru relay contacts to clean them. May solve your problem.
One caution use only a wood stick to clean out foreign matter you have charge capacitors on circuit board.

Jim Stewart · 12-20-2009, 12:03 PM

Did you say wood or metal on that stick?

hillbilly3 · 12-20-2009, 12:05 PM

Just looked one up on the net, it's just a basic power relay and is electrically held. As 007 suggested, turn the power off (both shore and generator). You may also use electrical contact cleaner to dislodge any debris. As RV Roamer said, it probally will not fail anytime soon, but it can get annoying!