Plugging into shore power.... Buzzing noise

soooo if I turn off the 2 main power 1 for the house batts, and other for motorhome disconnects, there should be any power at those wires ...... correct.

Slojoe72 wrote:
So the noise is coming from the automatic power switch panel. I took the cover off to investigate. It appears there is 2 switches, and 3 groups of wires going to panel. 1input from gen, 1from shore and 1output to the motorhome. When switch it activated either by shore or gen there is a black switch right in the middle that click in (on) and clicks out (off). The 1for
the shore power is what's buzzing/rattling. When plugging into shore the top switch clicks on and starts the noise. I left plugged in for a while and it was providing power to the motorhome. After a little while it started to quiet down to like an electrical hum, but would get loud again from time to time. I went over to the switch and with a screwdriver pushed on the black switch in the middle that clicks in and out, and noise totally went away. So do I just need to replace that one.... And where to buy?

Sounds like a heavy duty contactor, so just take it apart and clean up the rust and such from the laminated magnetic core or other. Remove the contacts and file or emery cloth them clean. Spray the whole thing with a non-conductive electrical cleaner which may be hard to find for any reasonable price. In fact I even use conductive stuff that will air dry pretty quickly.
Or......you can do what I've explained previously and be done with it all. After that, when you store away your cord, simply plug it in to your newly installed generator outlet and you should be good to go.

Yes, that is all you need.
Look closely for identification numbers. Post them!
What brand and model of transfer switch?

So the noise is coming from the automatic power switch panel. I took the cover off to investigate. It appears there is 2 switches, and 3 groups of wires going to panel. 1input from gen, 1from shore and 1output to the motorhome. When switch it activated either by shore or gen there is a black switch right in the middle that click in (on) and clicks out (off). The 1for
the shore power is what's buzzing/rattling. When plugging into shore the top switch clicks on and starts the noise. I left plugged in for a while and it was providing power to the motorhome. After a little while it started to quiet down to like an electrical hum, but would get loud again from time to time. I went over to the switch and with a screwdriver pushed on the black switch in the middle that clicks in and out, and noise totally went away. So do I just need to replace that one.... And where to buy?

I think I knew what he was thinking of doing, but connecting the GEN to the SP plug wouldn't do it without involving the ATS and having the same hum. It would require disconnecting everything inside the ATS. Yes he could make all manual by using plugs but today's ATS are pretty reliable and won't require you to go outside in the rain/darkness if you have a power failure.

mtrumpet wrote:
falconman, I'm pretty sure that what tropical36 is referring to is......Many gassers (my previous as well) didn't even have a transfer switch. When you were plugged into shore power, the power (obviously) went into the coach electrical system. However, when you unplugged from shore power, you merely plugged the shore power cord into an outlet (typically located in the power bay) that was wired directly to the generator. You could then run the coach on generator power. (The generator became the source of power as opposed to the shore power pole.) It was a very simple but effective system. Much easier to maintain and no expensive transfer switch to deal with. Frankly, I sort of liked it.

You got it and not any different than having more than one source of shore power to choose from. Unplug from one source and plug into the other, whether it be from the shore or another gen set. I've even plugged into a remote 1000watt generator when dry camping for saving noise and fuel, when just wanting to charge the batteries or for other small loads.
Just don't get it with these transfer switches and would be the first thing, I'd throw away if it went bad at all. Maybe in the beginning even, as it just might go bad at the wrong time and in the wrong place.
I mean you get yourself a 50amp range outlet from Home Depot (or maybe camping world in the case of a 30amp) and connect it to the output leads of the gen set. Connect the shore power cord to the coach main breaker box. After that, you should be able to choose either power source. Like I said and with some rigs, you may have to do something with the rear air generator circuit, like adding a 15 - 20amp relay of sorts.
I'd have to see the transfer sw., but first thought would be to use the empty unit for a junction box to house these connections.

falconman, I'm pretty sure that what tropical36 is referring to is......Many gassers (my previous as well) didn't even have a transfer switch. When you were plugged into shore power, the power (obviously) went into the coach electrical system. However, when you unplugged from shore power, you merely plugged the shore power cord into an outlet (typically located in the power bay) that was wired directly to the generator. You could then run the coach on generator power. (The generator became the source of power as opposed to the shore power pole.) It was a very simple but effective system. Much easier to maintain and no expensive transfer switch to deal with. Frankly, I sort of liked it.

I'm not sure Im understanding the question correctly but plugging the GEN output into the SP input would route the power from the GEN back into the ATS as SP and the relays would click and the hum would return. You could make it a manual switch by disconnecting the wires inside the ATS and replacing the two inputs, GEN and SP with female plugs and the output to the RV (inside the ATS) with a male plug. You might need to extend the wires to make it convenient and use the gutted ATS box as a junction box for the connections.
Going through all that doesn't seem logical to me. Connecting heavy guage wires is difficult to do properly and the required plugs aren't cheap. A replacement ATS is around $150 and would be much easier to install and probably safer.

falconman wrote:
You can try to clean it using compressed air but if it continues and it bothers you it will need replacing. It seems that older ATS used coils with AC switching and were prone to humming as the contactors wore. Older units also had the generator as the default so whenever shore power was present without the generator running you got the hum.
Newer models use DC voltage to switch the coils and the default is shore power, so no hum when plugged in. We just replaced ours with the newer version and it's dead silent now. They are not too expensive to buy but depending on the location it might be a simple or difficult install.

You seem to know and understand how this thing works, so let me ask you...and rather than replace the switch, why not just take the gen set output leads and connect up an outlet in it's place for the shore power plug?
I mean, you have to disconnect from the pedestal and store the cord away anyway, so how much trouble is it, to just plug into the gen set now? This eliminates the costly and sometimes troublesome and noisy sw. and you can only use one of them at a time anyway.
One might have to do something else with some units, like installing a little plug in relay from the 20amp gen feed for the rear air, but that's not much extra, if you're going to be doing some work here, anyway.

You can try to clean it using compressed air but if it continues and it bothers you it will need replacing. It seems that older ATS used coils with AC switching and were prone to humming as the contactors wore. Older units also had the generator as the default so whenever shore power was present without the generator running you got the hum.
Newer models use DC voltage to switch the coils and the default is shore power, so no hum when plugged in. We just replaced ours with the newer version and it's dead silent now. They are not too expensive to buy but depending on the location it might be a simple or difficult install.