creating 480 volts AC 1

[crazydave44]

I am looking to combine 4 hot legs from 2 standard generators to create 480 volts of outgoing power. Is this possible? If so, can someone help me out?

 

[alehman]

Not unless you have a way to keep the generators synchronized.

 

[waross]

A transformer is cheaper than a second generator. If you need the power of both generators, you can rig sync lamps to sync them in parallel on the transformers 240 volt input.
Running them in series will give you a voltage that varies between 0 Volts and 480 Volts.
It may be possible to put enough instrumentation on the generators to hold them steady but the cost of instrumentation and controls will cost much more than a 480 Volt generator or a 240V:480V transformer.
And it still won't work very well.


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[alehman]

I don't think it would work well at all. No speed control I know of can maintain accurate synchronization through varying loads an engine conditions.

You might have better luck connecting the two generators in parallel (if needed for capacity) and using a transformer to boost the voltage. The generators will need controls for parallel operation, but that is usually doable.

 

[davidbeach]

What the heck is a "standard generator" anyway? I'm surprised that there are any answers here as there is no where near enough information to even try to take a stab at it. If a "standard generator" even exists, it will have a three phase output, thousands of them are 480V. There is not even a mention of voltage in the original question.

 

[DanDel]

I've got to agree with davidbeach on this one, though I would imagine everyone else is assuming we're talking about two 120/240V single-phase generators, about 4kW, the kind you use for lights on a worksite.

 

[waross]

Is this possible?

Short answer;
NO
Long answer:
You can waste a lot of time and money to find out that the answer is;
NO
If no is not an option, look at locking both generators in step with a timing belt. Unless you have access to a machine shop it will probably be cheaper to buy a transformer or a 480 volt generator.
Well you may be able to sync the generators with a transformer floating on the windings. The transformer would not have to be full capacity but would have to supply enough current to hold synchronism. You could sync with a couple of lamps but without some more control gear expect early failure.
A theoretical yes turns into a resounding NO when practical factors are considered.


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[LionelHutz]

Ya, not much info on these gensets. 4 hot legs from 2 generators sounds like 2 single phase generators.

There is only one practical way I know of creating 480VAC, 3-phase from single phase. Use a single-phase input, 3-phase output VFD. The problem is that this type of VFD is typically only available for low power levels (like 5-10kW) and low power level gensets generally can't be paralleled. Also, the VFD is really just meant to power a single motor, not multiple or other loads.

 

[oldfieldguy]

If we're talking about your standard garden-variety small genset, small gas or diesel engine, self-regulating, self-excited, then trying to connect two is a no-go. They will interact in many interesting ways, none of them good, and one or both will likely fail. The trouble is that the two generators will "fight" each other for load because the references for the governors and voltage regulators is internal to the units.

In order to even begin to talk about them working together, the regulators and governors have to be designed and set up for parallel operation, and if we're talking about two single-phase generators, trying to get three-phase power out of them is theoretically possible, but impractical in my experience. LionelHutz's VFD idea is the only practical approach, unless you have access to an old MG set.

old field guy

 

[waross]

The OP didn't ask for three phase. Nevertheless it's a really bad idea for single phase any way. It's just not worth trying.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[jraef]

Short answer;
NO
Long answer:
You can waste a lot of time and money to find out that the answer is;
NO

I love that answer.


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