Community Forums

AKBrick · 06-22-2009, 07:01 AM

Hi All,
I haven't posted for awhile, so I guess things are going pretty well for CheetahGirl and I.

We run our generator to run the air conditioners while driving down the road to cool things off just before we park it for the night. We then turn off the air conditioners and the generator before plugging into 50amp service. Okay, finally here is the question. Can you plug into 50amp service while the generator and the air conditioners are running? That way all I would have to do is turn off the generator after being plugged in. It would be nice to just keep the air conditioners going when plugging in.

We are currently on the road to Virginia. We are doing the east coast this year before heading back to Casa Grande, Arizona for the winter.

Happy trails All,
Tom Brickwell

tom49 · 06-22-2009, 07:18 AM

I would not do that.
Unlike a UPS that keeps the power the same when switching sources there will be a large serge when the transfer switch goes to the park power (or to the Gen for that matter)
Best to turn off all electrical devices first, then switch sources of power.

Drifter · 06-22-2009, 07:33 AM

Do not do this. You may put your switch box at risk or burn up your A/C start up capacitors. Do not do this.

Elkhartjim · 06-22-2009, 08:05 AM

Consider also, most gensets need to run a few minutes either under no load or low load to cool down prior to shutting down.

gto19 · 06-22-2009, 08:10 AM

dont want to hijack the thread but is it ok to run the generator while driving down the road?what about in the mountains where the coach would be sloshing the oil all around in the generator?

Elkhartjim · 06-22-2009, 08:26 AM

I run mine over hill, over dell and over dusty trails. Just make sure the oil level is adequate. Besides, if it loses oil pressure, it'll shut down.

wa8yxm · 06-22-2009, 09:04 AM

When you have the generator running the shore cord is (if the Automatic Transfer Switch is working properly) completly disconnected from the rig (Save for the inlet to ATS wires) Thus you can safely plug in, no damage will happen provided the ATS is properly working... IN another thread here there is a poster talking about how his shore power cord is HOT when the generator is running.. HIS ATS is not working properly.

HOWEVER.. Turn off the air conditioners BEFORE shutting off the generator please... (If I had to guess I'd guess he did not shut off his A/C and water heater before transfering to shore power and that's how he welded his relays, but that is a guess)

The generator controls the change over. Just shut off stuff before changing over.

bullydogs1 · 06-22-2009, 09:15 AM

Can you do this? The answer is you can...but I can tell you I did it once with gasser (and the gene circuit breakers tripped) but I am such a fanatic with this coach that we always shut down the gene once we are about to put out the slides. I have the auto gene on once we set up so when we are about to leave, I cut power and then the gene kicks on. So can you do this once in a while---yes.....but I wouldn't make a habit of it.

MonacoMama · 06-22-2009, 09:15 AM

Quote:

Originally Posted by wa8yxm

When you have the generator running the shore cord is (if the Automatic Transfer Switch is working properly) completly disconnected from the rig (Save for the inlet to ATS wires) Thus you can safely plug in, no damage will happen provided the ATS is properly working... IN another thread here there is a poster talking about how his shore power cord is HOT when the generator is running.. HIS ATS is not working properly.

HOWEVER.. Turn off the air conditioners BEFORE shutting off the generator please... (If I had to guess I'd guess he did not shut off his A/C and water heater before transfering to shore power and that's how he welded his relays, but that is a guess)

The generator controls the change over. Just shut off stuff before changing over.

Hey Tom

...Sacs said the exact same thing - but he also said he does not worry about that 2 minute window between shutting the gennie down and plugging into shore power.

Sixpack98 · 06-22-2009, 03:02 PM

Might want to check with the manufacturer of the transfer switch. IOTA says the default is shore power so the IOTA might switch over from genset to shore power which could cause arcing of the contactor points and 15+ amps breaking and making might not be good for the IOTA. Also, the SurgeGuard may not like it either. I think I would play it safe and shut down the AC's.

Dutch Star Don · 06-22-2009, 03:48 PM

On a couple of occasions I've started my generator with the coach plugged in at the house. (This is the reverse of what you're asking.) It tripped my generator circuit breaker.

I personally would never try switching power sources with the A/C or water heater on because they are such a huge load that you are asking for trouble with the transfer switch.

Because I've tripped the circuit breaker on the generator running two power sources I would once again, personally not run two sources at the same time. I understand how the transfer switch works, but for the few minutes that you lose power it's not worth the gamble to me to fry the transfer switch. I also have the Surge Guard which is going to place a 2 minute delay and it may not like seeing the other power source.

Finally, I beleive the generator is the default for power, at least on mine, because it is the only power source capable of providing 50 amps to the coach all the time. (You may not always be shore corded to 50 amp so the generator is the default).

Flagelpater · 06-22-2009, 04:51 PM

My 05 Knight is wired to give the GenSet priority.

Sixpack98 · 06-22-2009, 05:59 PM

Don,
You are right, the genset is the default. Thanks for the clarification.

mrschwarz · 06-22-2009, 07:40 PM

Most automatic transfer switches are designed to carry a 50-amp load, but are not designed to switch while under full load. With a large load, you are risking burning out or welding the contacts.

At the same time, when the switch goes from one source to the other, you have a momentary drop in voltage. When voltage goes down, current goes up. This put a strain on the compressor.

You may or may wind up with a repair or failure, but you are asking more from the electrical system than it is designed for.