Another generator issue: voltage fluctuation

[belfert]

I had my two A/C units running from my shore power connection at home.  I started the generator and forgot to turn off the A/C units before I did so.  (Not good for transfer switch.)  Everything seemed to be running fine on generator power and I left it for about 30 minutes.  I came back and went inside and noticed the front A/C unit stop running and then the back A/C unit kicked in.  That seemed strange as both should be running on the generator.  While I was in the bus the back A/C unit quit and the front started running again.  I went to my breaker panels and noticed the transfer switch clicking on and off which should not be happening.  I pulled the cover from the breaker panel and measured the incoming voltage.  It would be right around 118 volts and then start dropping all the way to 30 volts.  The transfer switch would transfer back to shore power since the generator voltage was too low.  After a few seconds the generator would be back to 118 volts and the cycle would start again once the transfer switch transferred back the generator.

Any ideas why the voltage would fluctuate like that?  I checked the manual and the manual doesn't cover what I am seeing.  I have the generator running with electric heaters instead right now and the voltage seems to be holding.

[wg4t50]

Not a good nor proper setup allowing the genset to be the controller between normal power & genset. 
The power should stay connected to normal then switch to genset when normal is disconnected.
Sounds like an neutral issue, so without looking at it, that would be my first guess to look at.
Dave M

[belfert]

The IOTA transfer switches if you wire them the way they are labeled it will automatically switch to generator as soon as power appears from the generator.  The default is shore power.  I could certainly reverse the wires inside the transfer switch, but not sure that is a good idea.  The way it is now there is a delay before the transfer switch transfers power.  The delay allows the generator to get up to speed before transferring the load to the generator.  I normally shut off any big loads like the A/C units before starting the generator, but I forgot today.

The second time I started the generator it didn't seem to have any problems with voltage.  I plugged in two 1,500 watt heaters after a bit and no issues.  Today was the first time the generator had any real load on it since last fall so maybe it didn't like being unused that long.

I'll check the neutral inside the transfer switch and the breaker panel.  The neutral at the generator is good unless it is bad down by the head.

[wg4t50]

No matter how it is rigged up, I get concerned when every time you start the generator while connected to the outside power, it switches, very bad feeling.

As for it running OK, now, give me the idea there is some connection issues somewhere, maybe ow the transfer switch is wired in too.

There are generator experts behind every tree, and there are many trees, so do what you think is best.
Dave M

[belfert]

Dave, I checked every single connection in the transfer switch, generator, and breaker panel.  None of the connections is loose.  The generator produces the right voltage every time now so I don't know if it was just a one time problem or not.

Basically, the only time I have a shore power is at home so having generator priority is fine for me.  How is your Foretravel wired?

[wg4t50]

I suspect the issue is not cleared up, but will sow up again at some bad time, it may only happen wile connected to the outside power, that would be more scarey, either way, there is an issue lurking.
The Foretravel uses the auto transfer switch with normal priority, generator never connects unless the power post is off/disconnected.

My game is emergency generators for past 40++ years, it is closer to a hobby as I love the game, the sad part to see such dangerously wired home creations that are begging for a dissaster.
In the generator business, when they are properly installed, they have very few issues, only the poor installations have non stop issues untilthey are corrected.
Just my opinion along with the NEC
Cheers
Dave M

[wg4t50]

I forgot to ask, is this setup for 120 VAC  or 120/240 VAC, if the 120/240 setup, I would be looking very close at the neutral line and would not be surprised if when the voltage drops, it goes up the same amount on the other leg.
Dave M

[belfert]

I talked to Powertech today and they think the brushes might still be an issue.  I did ohm out the brushes and they are right at 60 ohms which is within the range specified.  I'm probably going to have to pull out the generator again and replace the brushes.  I'll replace the bearing if I have to do that.  I'm sure the fine talcum like dirt out in the desert is causing issues.

I have an IOTA RV transfer switch and it isn't some mickey mouse install.  Every RV transfer switch I could find on the web today states that they will switch to the generator automatically if there is voltage sensed on the generator terminals.  Foretravel must be doing something different.  I may just do a manual transfer switch with plugs like a lot of guys do since I am always on generator when away from home.  The hard part would be remembering to change it back when I got home.

My generator is set for 110 volt only right now.

[wg4t50]

Good, glad your on 120 VAC, and Foretravel uses a good 50 AMP ATS, 120/240 Volt, it does not jump to the generator unless there is no powser on the normal side, and with about a 3-4 minute time delay,  when I get home, turn off genset, thenplug into the home 50 Amp plug, no delay.   I  would have rearranged already if it went to the genset while plugged in to the power post,  but not needed.

Never knew the Marathon Pancake from China, when I purchased mine it was wound in Lancaster Pa, where I picked it up. Put over 6 k hours on it with ZERO issues.   That origional Pancake design was sold to Marathon, so who knows were/how it goes today.
Good luck
Dave M