Automatic Transfer Switch (Power Switch)

[Ragman]

After recently arriving home from a long trip, I was running the generator with both A/Cs on and it suddenly stopped providing electricity to our motor home. (The generator problem is another subject.) As the A/Cs went off, I heard a chattering sound. I initially thought the generator motor was dying, but realized it was still running, but not providing power to the MH. So I killed the generator.

Then I plugged in to shore power and still got no electricity, so I checked all the breakers, including those in my garage and none had blown. Then I noticed I was getting electricity to the built-in surge protector but none beyond it. Then I assumed that the auto transfer switch wasn't switching.

I disconnected the land line, turned off all electrical appliances and started the generator again. I was getting power, but it was only up to about 100 volts with no appliances on. I turned off the generator and plugged back in to shore power. Again, the surge protector showed it was getting electricity, but not beyond it. I left the MH plugged in to shore power and this morning (the 4th day) we had electricity. Undoubtly, the auto transfer switched over to shore power.

Has anyone out there had this type of problem with their transfer switch that could give me advice?

Happy Trails,
Larry

[RJay]

Hi Larry,
Take the cover off the transfer switch and check it carefully. You may have a problem with one of the internal relays.

[wa8yxm]

I agree, measure voltage at input to transfer switch, and at output.. NOTE: the voltages in the Transfer switch can be confusing, always measure hot to neutral, never across the hots if there are more than one.. (Simply avoids confusion) shoudl be about 115-125 volts hot to neutral.

if the input voltage is low, measure at the generator's OUTPUT, if that's low break out wallet cause it's a generator issue.

If Generator normal, ATS in is low, check all connections between the two (There is a junciton box usually) as many RVer's have a few screws loose, and the wire nuts on these junctions, or the screw that holds the wire if it's that type, are the kind of screws I'm speaking of. If input to the ATS is normal and output is low, You have fried your contactors (Another name for RELAY usually a BIG relay)

(3 names for same (electroincally) device, Relay (low current) Solenoid (High current low voltage) Contactor (High currnet high voltage) all electroincally identical, just some are BIGGER than others)

You may be able to clean the contacts if they are open.. Visual inspect (power off) and burnish.. You may also have other issues inside the box not so easily fixed.