Community Forums

Patti Brown · 04-10-2016, 10:34 PM

Don't know if anyone is up this late, but when we went to bed we heard a distinct, persistent humming sound we have not heard before. Went outside to check and it is coming from the automatic transfer switch box. EMS reads normal. All systems seem normal. I don't know if we should be worried or not. I am sufficiently bothered by it that I am having trouble going to sleep. Is it something to worry about or not?

dons2346 · 04-10-2016, 10:39 PM

Don't worry about it yet. When mine started humming, it wasn't long before I had a failure. Don't worry, it isn't going to catch fire

Vacay Wheels · 04-10-2016, 10:42 PM

Oh yeah, mine does this too. Really hope it fails in the next couple months while it's still under warranty!

dennis45 · 04-10-2016, 10:42 PM

Quote:

Originally Posted by Patti Brown

Don't know if anyone is up this late, but when we went to bed we heard a distinct, persistent humming sound we have not heard before. Went outside to check and it is coming from the automatic transfer switch box. EMS reads normal. All systems seem normal. I don't know if we should be worried or not. I am sufficiently bothered by it that I am having trouble going to sleep. Is it something to worry about or not?

I would unplug from shore power and go into the connections to make sure they are all tight. It could just be a loose connection causing it to hum.

Patti Brown · 04-10-2016, 10:44 PM

Quote:

Originally Posted by dons2346

Don't worry about it yet. When mine started humming, it wasn't long before I had a failure. Don't worry, it isn't going to catch fire

Ah, you read my mind! Thanks so much for the reassurance.

When things electrical start making noises they shouldn't 't, my mind goes to all sorts of worrisome places.

Patti Brown · 04-10-2016, 10:46 PM

Quote:

Originally Posted by Vacay Wheels

Oh yeah, mine does this too. Really hope it fails in the next couple months while it's still under warranty!

Okay, now I can go to sleep. Thanks, James.

I was really hoping you were up!

Mr JP · 04-10-2016, 11:07 PM

We Lost our transfer switch on our outing this trip here's a picture of a burnout transfer switch and yes the wires will burn

Click image for larger version

Name: ImageUploadedByiRV2 - RV Forum1460351118.667008.jpg
Views: 352
Size: 85.4 KB
ID: 123784

Click image for larger version

Name: ImageUploadedByiRV2 - RV Forum1460351194.123995.jpg
Views: 287
Size: 53.2 KB
ID: 123785

Good Luck
JP

dennis45 · 04-10-2016, 11:32 PM

Quote:

Originally Posted by Mr JP

We Lost our transfer switch on our outing this trip here's a picture of a burnout transfer switch and yes the wires will burnAttachment 123784 Attachment 123785

Good Luck
JP

I rest my case,

Mike and Cha · 04-10-2016, 11:35 PM

Is your inverter in the on position, we get a little humming from that too. Also our transfer switch has always had a little hum to it, very minor and only hear it when it is super quiet outside, but it is noticeable at times. Had it checked when we originally bought the MH, and were told the level of sound from both was normal and not a problem. That was two years ago, and it hasn't gotten any worse. We keep our MH plugged in all the time so I would think if it were a problem it would have gotten worse or quit working by now.

Mr JP · 04-10-2016, 11:40 PM

All of the lugs were tight all I can figure is the contacts were corroded not making good contact. We had no pre-warning just half of the coach all of the sudden lost power when I went out and investigated that's what I found I would agree disconnect from shore power and investigate in the morning

Good Luck
JP

Romeo · 04-11-2016, 08:21 PM

My transfer switch went out last June... mine looked a lot like MrJP's picture above. The box did get really hot and started melting the plastic case. So I think that it could be a fire hazard, although I am a little late with this information. However, my understanding is that a transfer switch will hum at times without indicating that it is going out or is defective.

When I purchased my new switch there was an option for a switch that would not hum and was a little more in expensive. I selected the less expensive switch since the hum was not bothersome to me and my old one did hum occasionally.

It is a good idea to disconnect all shore power, and of course have the generator shut down, and check the lug screws to make sure all the lugs screws are good and tight. That is done by opening the transfer switch box exposing the connection lugs.

Old Scout · 04-11-2016, 08:31 PM

Good idea to check the connections....If you decide to / need to replace it later--I would recommend looking at the Lyght product line. Cheaper units have AC current contactors that hum more and more over time. Suggest getting a unit with DC contactor--no hum......

KenSherwin · 04-12-2016, 06:36 PM

Quote:

Originally Posted by Patti Brown

...we heard a distinct, persistent humming sound...

Smart alec answer #1: Maybe you should teach it the words.

Smart alec answer #2: Melody or harmony?

Useful answer: What they said.

Sorry. I missed my nap today. This work stuff is starting to get in the way.

Dr4Film · 04-12-2016, 06:51 PM

Most of the time if there was no humming previously it is usually from dirty contacts and needs a good cleaning and tightening of the connections.

If it has always had a hum, then it is because of the 120 VAC coils used for relays in the ATS versus an ATS that uses 12 VDC coils to activate the relays.

An example is the ESCO ATS model number ES50M-65N which uses 120 VAC coils versus the ESCO LPT50BRD ATS which uses 12 VDC coils.

Dr4Film ----- Richard