Generator Switch Box

[Darrell Snell]

(02-28-2013 17:20)pgchin Wrote:  Darrell,
David gave you excellent advice on troubleshooting the powertech. I have not seen this before on the bird BUT, I have elsewhere. If it were me, I'd do the resistance check David suggestion and if its good, then rewire again. Keep the AC unit that pegs leg 2 OFF and try and turn on a few things so you can get a 20-30 amp load on both legs, then see where you are at with the new wiring. The only other things I can think of for a SWAG would be the bearing is starting to go but there is no way to check that without tearing the head apart. Take a peak at the voltage regulator if you can and see what kind of shape it's in.......
The AC unit that pegs the meter probably has a bad or weak start motor capacitor or the compressor is shot. I'm willing to bet your Blueberry farm on it! hashahahahah-just clowin around! Seriously Have seen this MANY times. Climb up on the top of the bus, remove the AC cover (4 screws). Then remove the metal cover that covers the system and forms the air compartments, about 10-12 sheet metal screws. That starter cap should be on the curb side. You can use your ohm meter to see if it's shorted........ very common deal, maybe its causing the genny to overload leg 2? (SWAG) Please BE CAREFUL up there, Donna always hangs around while I'm up there so she can catch me if I fall! If the cap is bad, you can get what you need locally at any appliance parts supply store on the cheap. They will match it up for you. If the compressor is bad,,,,,,,uuhhhhhhhhh use 2 ac's :-) until you save up for a new one! FWIW I have one that's starting to do exactly that and I Know the cap is good so I do not use it anymore and will replace it.......its on my punch list! It's the middle one so the front and rear AC keep the coach comfortable most of the time.

More info on generator transfer switch.
Thanks to you both for the insight and direction.
Once again I ran all 3 AC's under load (had to set the thermostats at 40F) and observed the amp gages. During normal cycling of the AC's no current spiking was observed. The replacement 10 ga wire didn't get warm, no smell or smoke and my clamp-on amp meter agreed with the coaches. About 12amps per unit under load.
If I manually start an individual unit while there is a demand in that zone I will see a prolonged spike on the meter of which ever leg that unit is wired to. I haven't had the guts to leave it on for more than 3 to 5 seconds and the 20amp breaker doesn't trip. This happens to all 3 units including the center unit which was replaced last spring.
Yes indeed the transfer switch comes from the factory with 10ga wires between both sets of T1 and T3 terminals and one 6ga wire between the T2s (white neutral). The balance of the terminals were wired by BB with 6ga.
Should there be some logic in the AC units or the thermostat that delays engaging the compressor until the motor has started?
Why don't the breakers trip?
I'm pretty sure this condition is what fried the earlier 10 ga wire.
Nice to have the Aqua Hot last night, warm floors too!
D