For gen techs

[gtnsmlr]

I'm running my 50A rv service with a Honda EU6500 connected to the 30A 240V receptacle. Everything works fine. My question is, would long term durability be improved if I switched to the110V only setting and fed the RV panel with the hot legs from the 30A 110V receptical and the 30A 240V receptical, Note: when the gen set is set to 110 only, the 240V receptical only has one leg energized.

[gtnsmlr]

thanks guys, case closed

[MEXICOWANDERER]

Do your own testing by measuring heat with an IR gun.

[wa8yxm]

The advantage of the 240 volt outlet.. Assuming it is wired like I think it is. (120-120 or 240 across) is that the neutral wire carries no or less current.

Imagine you have ONLY two identical Air Conditioners running

Current flows up L-1 (With the associated voltage loss) and and back down L-2 (Again with associated voltage loss) To make the math easy let us assume 1 volt. NOTE 1 volt is just to make the math easy.

THe result is each A/C is quite happy with a precieved voltage of 119 Each>

Now let's use the 120 volt outlet.

Each leg, in the motor home Still carries the current for ONE A/C with the associated 1 volt loss.

But the NEUTRAL carries the current from BOTH with .. as a result. 2 volts loss And in addition it is now carrying more current than it is designed for (Fire Danger).

So the A/C's now see 117 volts.

And this is why houses are wired 120/240 as well as 50 amp RV's

[KD4UPL]

I say you're over thinking. Either way you are well withing the limits of the device. I have never heard of or experienced an inverter failure in a genset.
The other problem you may create is that you could potentially overload the neutral in your cord if by going to the 120v setting the current in L1 and L2 is in phase. This gives you the possibility of having over 50 amps flow thru the neutral. (But this is very unlikely to occur unless you load everything on one leg on purpose.)
You would also have a greater voltage drop in your line cord if you were 120v only instead of 240v. As short as the cord is that's probably not a big deal but something to think about if you go running a long extension.
Leave it in 240v.

[MrWizard]

70% of one 23amp leg
due mainly to running only (1) A/C unit

your dealing with electronics, not mechanical
as long as you are under the rated capacity, and the inverter module is staying cool
you gain 'nothing' by also warming up the unused inverter section

i suggest leave it alone

[gtnsmlr]

My question seems to be getting lost in the translation, let me clarify. I have a big 5ver with a 50A service and two ACs. The panel loads are balanced within 10% and the generator runs everything just fine and in that respect I have no problems. I was reviewing the generator manual, specifically, the 240 or 110V switch. It appears that the EU6500 has two inverters to provide 240 and the switch bridges the inverters to provide 110V only. This sparked a thought. As currently connected to the generator via the 30A/240 4 wire receptical, with the 15K AC on, one of the inverters is carrying the AC load running at around 75% of its max rating. If we went to 110V mode, thus bridging the two inverters, wouldn't they both be running at around 40% with the same demand ? equaling less wear and tear? Or, am I over thinking this whole thing and pecking at catchup packets...

[road-runner]

Chris Bryant wrote:
Keep in mind the generator is a 3 phase which is, I believe, rectified to do, then run through the inverter, so the load on the generator is the same either way, instead of load on windings, it will be load on inverter. That said, it would probably be easier on the inverter, but I've never heard of a Honda EU series inverter failure.

That's what I would have thought, but a look at the wiring diagram reveals that the eu6500i has dual 3-phase windings, feeding separate inverters contained in a single physical module. The windings and inverter outputs are identified as "M" and "S", which could mean "master" and "slave". I've noticed a couple reports of eu-series inverter failure over the years, but they are extremely rare.

[MEXICOWANDERER]

Without question per lbs of fuel consumed fewer kWh are generated when loads are imbalanced. The 6-8% loss of economy is enough to have encouraged me to install a Scott Connection 3-phase to single phase transformer setup on my genset and to use a toroid wound transformer to obtain balanced single phase 120vac from the Scott connection transformers. A twenty gallon day-tank with markers does not lie. Nor does a 3-phase General Electric kWh.

The issue is for small systems is all this (for single phase) worth it?

Within 10% of a balanced load as determined by individual kWh measurement of a 240 single phase system I would have to say "no". I excess of a 30% difference the balancing is worthwhile only if the system is large enough to make the single digit percent economy gain worthwhile.

A single phase generator winding running at 70/30 imbalance makes the whole generator operate at a higher temperature. This is fact not conjecture.

Crunching numbers will reveal any relevancy to pocketbook impact.

[Chris_Bryant]

Keep in mind the generator is a 3 phase which is, I believe, rectified to do, then run through the inverter, so the load on the generator is the same either way, instead of load on windings, it will be load on inverter. That said, it would probably be easier on the inverter, but I've never heard of a Honda EU series inverter failure.

[Yosemite_Sam1]

Motors and engine's longevity is measured on running hours -- and extended by good maintenance.

[MrWizard]

you ask about rewiring plugs, using two plugs while in 120v mode
to spread the load, take load off one winding

you have inverter generator, the only windings are in the output transformer of the inverter

the 'best' way to solve the perceived issue is to balance the loads in the breaker panel

[gtnsmlr]

MrWizard wrote:
what else is using 120v power
fridge ? water heater ? converter ?

might be better to just swap some breakers around in the power center
to balance the load
put them on the other leg

you have 23amps per leg in the 240v mode using the (4) wire 240v outlet

moving circuit breakers to shift and balance your load is the best option

you have an unbalanced load , it will still be unbalanced even on 50amp shore power

this is NOT a generator problem

Never said it was a generator problem.

[MrWizard]

what else is using 120v power
fridge ? water heater ? converter ?

might be better to just swap some breakers around in the power center
to balance the load
put them on the other leg

you have 23amps per leg in the 240v mode using the (4) wire 240v outlet

moving circuit breakers to shift and balance your load is the best option

you have an unbalanced load , it will still be unbalanced even on 50amp shore power

this is NOT a generator problem

[gtnsmlr]

DrewE wrote:
I don't think it would make a big difference in your case in terms of durability. I would suggest using the 240V setting
. (In theory, it could be possible to work better with an unbalanced load where one leg is more heavily loaded than the other with proper wiring of a cordset combining the two 120V outputs from the two twist-lock connectors when running in 120V mode, but errors in making or using such a cord could be problematic or even dangerous and I think the gains would be minimal in practice.)

This is my line of thought. Currently with the 15k AC running and the gen in 240V mode on leg is running at around 75% of max load. With 0 on the other. It would seem to me, going to the 110V mode would bridge the two outputs and run at around 50% with less wear and tear on the windings in the long term.