Strang Electrical hum

[knapper42]

We have a 2018 3560RL Montana and we can hear a low hum when we stand by the stairs. That is right next to the breaker box and switches in the cabinet above.
We can power down the frig and turn off the battery disconnect and still hear it.
I thought it might be an inverter because we don't always hear the sound.
where would the inverter be installed and could the sound be from something else?
Anyone experience this.
Knapper

[Carl n Susan]

Your model (3560RL) indicated you don't have a residential refer so you don't have an inverter. But what you do have is a converter as part of the fuse panel. It has fans and can make noise. Pop the door on the panel and check if if that is what you are hearing.

[DQDick]

You will only have an inverter if you have a residential frig or have installed it yourself. The converter on the newer rigs is usually under the breaker box.

[knapper42]

Thanks that is what it has to be. We have opened the door on thebreaker box but it wasn't apparent to us that the sound was coming from that area. Thanks for the help and the next time I will recruit someone with young ears.
Knapper

[jetskier]

Do you have the generator prep or generator? The ATS is located on the back of the stair. The contactors in the ATS make a low level humming sound.

[twindman]

Try listening to the hum while turning on 12V light switches one at a time. I can hear the hum as each light that goes on makes the hum louder/faster. My understanding is the fan on the converter is a variable speed fan, so it does change speeds.

[rohrmann]

One of the 120 volt breakers in the panel will be for the converter. When you can hear the hum, turn off the converter breaker and the hum should stop.

[Barefoot Bill]

I concur that the hum is from the converter fan. On our 2007 and 2010 3400RLs, the coverter is under the stairs, not behind the electrical panel, so the hum comes from the stairs. And yes, turning on fewer or more lights changes the hum sound.

[jetskier]

I just went out to the trailer and I have a very small hum from the transformer in the converter when I flipped the breaker on. I usually keep it off cause my solar keeps the batteries charged. However, the coils in the genset/shore ATS produce a much louder hum. So there's the two sources. My second 50amp ATS between my inverter and main panel is a lot quieter or it's overpowered by the main ATS noise.

[knapper42]

I did confirm that the hum is coming from the ATS box under the stairs. The converter fan probably has a hum but doesn't seem to be as noticeable