Exercise genny while on shore power?

In conditions such as changing 120v power inputs
Or generator restarts

I give the AC at least 5 minutes of fan only run time, to reduce internal heat, and head pressure on the compressor, this reduces lock rotor amps on the compressor motor thus lower startup load, when switching to cool mode
A really big help when using a generator to power the RV AC

Thanks, Mexico & Bobbo

Boon Docker wrote:
I'm curious, why the 3 minute wait?

Air conditioner compressor head pressure. Turn off the air conditioner and you don't need the 3 minutes.

It may allow for gas pressure compressor bleed down.

I'm curious, why the 3 minute wait?

Ok one rule when switching from GENERATOR to SHORE or back is OFF for 3 minutes

So As someone up thread said
Go out. Flip breaker to OFF,, go back in side, count to 3 minutes and Crank that puppy up... shut down and 3 minutes later (See note) flip breaker back on

Option 2: Flip main breaker in RV Inside) off Wait 3 minutes. Crank it up And then reset breaker. When done flip breaker off. Kill genny, wait 3 minutes and flip back on

NOTE: I rigged my rig with a "SURGE GUARD" (TRC/Southwire) unit in line with the SHORE power only.. So I shut genny down went out and flipped breaker on and the TRC counted down the better part of 3 minutes. Then CLUNK power on.

I had a somewhat unique power install

Shore----Hughes Autoformer installed.. Hard wired TRC/Southwire Surgeguard converted to plug in----- Auto transfer switch.

When the RV was "Totaled" I pulled both the Autoformer and the surge guard.

And now.. For a radio net so end of post.

Bobbo wrote:

I'm glad you said "very little possibility for it to connect to both at the same time." That is tacit admission that it is possible and could happen. That is the perfect rationale for unplugging first. Small risk but large consequences, with piddly (a technical term) effort required to absolutely prevent.

Yes, I admit that it is possible. Lots of things are "possible". But understanding how an ATS works tells me that it is highly, highly improbable for the ATS to connect to both shore and generator at the same time. Switching with heavy loads can cause arcing and damage the contacts, possible making them stick, but they can still only make contact with one side or the other, not both. An ATS is just a large relay.

Yes, we hear of the occasional claim of it happening, but very seldom (among 100s of 1000s of RVs in use), and never have I been convinced that what the poster "thinks" happened actually did.

edatlanta wrote:
My 3rd ATS is going strong, but I do now check the wiring lugs inside the unit once a year to make sure they are still tight.

Things that go bump in the night or bump up and down highways need to be checked.

I took my service panel cover off to access my converter and clean all the sawdust they left in there. I found many loose wires all over the place. 120v. 12v side. I checked every single screw i could find.

My friend has a toyhauler. Noticed the 120v outlet in the bathroom had black smoke marks. Sure enough the connnections in the back were loose and arcing.

magicbus wrote:
Is it COVID or do people normally worry this much? If you have to ask the question, just go out and flip the breaker on the pedestal to OFF.

Dave

ZACTLY!!!

We all have our story based on our experiences so here is mine.

I full time since August 2010. I have an onboard Onan and exercise it every month for one hour under load. The load will be a/c's in a/c season and electric heaters in heat season. I NEVER fail to exercise it and it works great whenever I need it and it has a little over 600 hours on it now.

I always turn off my main breaker at the power pedestal when I fire up the generator. During the past 10 years I have had to replace 2 ATS's. The first one that failed was replaced with a different brand due to the original one not being produced any longer and was ultimately recalled by several RV manufacturers. The second one failed due to burned wiring inside the ATS which I think was caused by loose wiring lugs. My 3rd ATS is going strong, but I do now check the wiring lugs inside the unit once a year to make sure they are still tight.

Things that go bump in the night or bump up and down highways need to be checked.