rk911 wrote:
the default state of an automatic transfer switch is GENERATOR. when you plug into shore power you should hear a loud THUNK sound caused by the ATS electromagnet switching FROM genny TO shore. it may take 5-10 secs for the EM to switch. conversely, when unplugging from shore power you should hear the same THUNK of the EM back to genny.
since shore power is working unplug and listen for the THUNK sound. if you don't hear it you either don't have an ATS or it's stuck on the shore power side. sometimes you can unstick the ATS by lightly tapping on the ATS with a rubber mallet. if you do hear the THUNK the circuit breakers ON the genny may have tripped. check to be sure...don't just look at them.
Most transfer switches I've encountered are set up so that, absent any power from the generator, they are always set to shore power. The generator power being present causes it to switch over to the generator, after a time delay; shutting off the generator lets it switch back. Hence the generator does have priority (after the time delay), but there's no clack or clunk when connecting to shore power. There are a few different designs of transfer switch, of course, so any statement about when it clunks is probably not universal.
The automatic transfer switch is usually located near where the shore power cord comes in or where the AC electric panel is (which often is in the same general vicinity). Mine is attached to the back of the AC distribution panel.
Definitely check the circuit breakers on the generator. Sometimes they can still look like they're in the on position after they've tripped, so it's a good practice to flip them off and on if you suspect them at all, rather than just looking at them.
