same gennie, different question

stlthe · 02-10-2021, 06:07 PM

my gennie (onan qd5500, single phase) puts out arount 125V on each of 2 local 30 amp breakered circuits, and about 125V when i measure across the 2 hot wires. Does this mean i could conceivably tie them together for 1 50amp circuit at 125V, or am i measuring something wrong?

I have no real beef with 2 30A breakers (call them what you will, i know they do not put out 60amps) but would prefer to allocate my elec as i see fit in my own panel, by breaking down the wattage as i see fit.

given the measurement in the 1st paragraph, could i combine them into 50amp for simplicity, as in would match a 50amp shore power cord, so i could install 50amp outlet on gen, instead of the 2 20 amp connectors i have on there now?

i would like to have 50amp output connector from gen, 50amp output connector from shore, and 1 50amp input for the bus, for simplicities sake.

should i be able to tie the 2 gen outputs from paragraph 1 into a single 50amp output so i can use a common shore power setup? i know the difference between 45 and 50 amps, and would certainly account for that in my usage.

thanks

Evan

Rivetboy · 02-10-2021, 06:35 PM

It depends. There are 2 models The 2860 is a single phase 125 volt output which is what I think you have. The 2861 is a 120volt/ 240 volt dual phase model.
Since you measured across both "phases" and only read 125 volts you have the single phase model 2860. It is 2 circuits connected to the same output (single phase)

Rivetboy · 02-10-2021, 07:34 PM

So what you really have is one 125 volt 25 amp circuit that is connected to two 30 amp receptacles in parallel.

rffffffff · 02-10-2021, 08:26 PM

I know nothing of these generators but if you measured across two phases and got 125v then I think connecting them will be bad. If they are truly in parallel to each other and a single phase you should see zero volts across them because they should be he same.

Maybe you measured hot to ground and hot to neutral? Either way, don’t wire two things together if you measure 125v between them because it’ll be unpleasant!

Rucker · 02-10-2021, 08:32 PM

Hang on-you can't push 50 amps through a 125V line-max is really ~20 amps or a little more. These generators are designed to provide up to 50 or so amps at 220V. The AC means alternating current. The wave form of the two leads is 180 degrees out of phase with each other, which is how you get 50 amps-when one lead is pushing, the other is pulling, so to speak.

My Onan 6.5K gets wired into a subpanel that can provide 110 or 220. The 110 is one lead plus the common; the 220 is two leads plus the common. I can't pull more than ~30 amps out of any 125V lead. However, I can have as many branch circuits as will fit in the subpanel.

I'm sure there are plenty of youtube videos on this.

Why would you need more than 5 or 10 amps on any particular branch or device?

bus-bro · 02-10-2021, 09:56 PM

I would wire my 240v subpanel with two legs of 120v loads, then wire one of the generator output legs to one side of the panel, the other output to the otherside of the panel. This is a common way to wire an RV with a 50 amp service, just can't easily have 240v appliances installed.

Rivetboy · 02-10-2021, 10:08 PM

Without regard to what you measured what are the last 4 numbers on the nameplate that is what you have

Rwnielsen · 02-11-2021, 01:07 AM

If they were on the same phase you'd have measured zero between the two hots. If it's split phase you should read 240v. Hot and neutral are 120v, two hots and a ground are 240. There is no common in AC. There is a neutral and a ground. The neutral is a current carrying conductor and the ground is not.

Booyah45828 · 02-11-2021, 08:58 AM

It depends on the generator head that's used. I'm not familiar with that specific model in order to tell.

Listen to rivetboy, he seems to be familiar with them.

My custom generator is a single pole 2 coil head, how I connect the coil wires in parallel vs in series determines the voltage created. Parallel gives me 50 amps of 120vac, where as in series gives me 25amps of 120/240vac.

What I don't think you're realizing though, is that a 50 amp panel provides 12,000 watts. So even though your generator might pull off the 120/240 aspect of a 50 amp panel, it will never have the wattage a 50 amp panel provides.

stlthe · 02-15-2021, 05:28 PM

Quote:

Originally Posted by Rivetboy

Without regard to what you measured what are the last 4 numbers on the nameplate that is what you have

sorry for delay, embarassed to say i must not have read the question. 2733C is the end of the nameplate. picture is poor because it was taken for a different purpose.

stlthe · 02-15-2021, 05:32 PM

Quote:

Originally Posted by Rwnielsen

If they were on the same phase you'd have measured zero between the two hots. If it's split phase you should read 240v. Hot and neutral are 120v, two hots and a ground are 240. There is no common in AC. There is a neutral and a ground. The neutral is a current carrying conductor and the ground is not.

thanks, i must have wired them wrong, ahh, i never tested 2 hots and a ground. i tested what i thought was hot and hot and got 125V (i attached 1 20AMP receptacle with 30ga wire to each output circuit.

stlthe · 02-15-2021, 05:42 PM

As i looked again at the nameplate it says 45amps, i was just thinking i had that much to work with since it is one phase. I guess I better not try connecting them.

I'll try to get a clearer picture

Thanks Evan

stlthe · 02-15-2021, 05:58 PM

Quote:

Originally Posted by Rucker

Hang on-you can't push 50 amps through a 125V line-max is really ~20 amps or a little more. These generators are designed to provide up to 50 or so amps at 220V. The AC means alternating current. The wave form of the two leads is 180 degrees out of phase with each other, which is how you get 50 amps-when one lead is pushing, the other is pulling, so to speak.

My Onan 6.5K gets wired into a subpanel that can provide 110 or 220. The 110 is one lead plus the common; the 220 is two leads plus the common. I can't pull more than ~30 amps out of any 125V lead. However, I can have as many branch circuits as will fit in the subpanel.

I'm sure there are plenty of youtube videos on this.

Why would you need more than 5 or 10 amps on any particular branch or device?

You must be right abt youtube, thanks for that tip, ttytt it had not ocurred to me. this is not really a bus question at all.

I have 2 air conditioners, and was thinking with a 50 amp panel i could run a third, granted part of this question is hypothetical (since 45 amps would not reliably run 3 full size a/c units anyway), lets say they are 5000btu window units and i wanted a circuit for each.

i only have 2 circuits coming out of the genny and was hoping to combine them, then split them again.

Thanks

Evan

Rivetboy · 02-15-2021, 07:32 PM

Nameplates are your freind
It is a 120 volt genset with two 20 amp circuits that are separate windings.
That is why their is no 220 volts across each circuit. Great that it is a 2 circuit genset and super great it is diesel( had the same one in gas years ago) too bad it is 3600 rpm as opposed to 1800 rpm. Still a very robust and reliable piece of equipment, just noisier.

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