Tying 2 10k generator heads together

[artieb]

Hi, I have 2 identical 10Kw 240 vac, Harbor Freight generator head units. I understand that each needs to be turning the exact RPM. Would I be able to use L1 and L2 in sine wave harmony?
Would I need to time the sine wave, to be sure each is following the same wave? Would the total output 20kw?

 

[mike93lx]

No idea how you could sync them up without buying equipment that would be more expensive than a 20k generator. For units that can be paired (only inverters, AFAIK), the systems are built in.

 

[The Cobbler]

some ( like Honda) have sync cables for their smaller inverter generators. , but the short answer is, no you cannot get them synced to run together

 

[artieb]

I have several oscilloscopes

 

[mike93lx]

I have several oscilloscopes

How are you going to sync them? There is no mechanism for adjusting that

 

[The Cobbler]

can you re think your plan & run both generators , each powering separate devices and not tied together in any way ?
like 1 generator powering fridge, freezer etc, the other generator powering table lights, microwave , toaster etc

 

[dogdog]

I have several oscilloscopes

what is an oscilloscope?

maybe give HF a call and see if the generator that you have can be parallel together.

their manual for the 9500Watt inverter generator says you can get a parallel kit.

https://manuals.harborfreight.com/manuals/59000-59999/59188-193175459091.pdf

Follow parallel Kit instructions provided with
Kit for connection and use of a parallel Kit.
2. Only connect two identical Inverter Generators
together using a Parallel Kit.
3. Connect Parallel Kit only to terminals marked
“Parallel Outlets” on the front of the Generator

 

[ihateminimumwage]

No, you're not going to be able to sync them. Even trying to set one as leading and one as lagging won't do anything as a decent size load bogging the engines down would throw them out of sync.

 

[Jim_No_Garage]

I read that he has 2 10KW HF generator HEADS - not complete generators.

If here could run the 2 heads off same the power input (not sure what you power a 20KW load with) you MIGHT be able to get them into synch and work additively. That's purely theoretical - I took (and failed) a Power systems class while attempting to become an EE in college so WTF do I know?

The 2 rotating inputs to the generator heads would be connected via chains/gears/duct tape and the engine powers both generator heads together. You would have to get them mechanically into phase power cycle wise but then as long as the binding mechanism doesn't allow the 2 heads to "wander apart" rotationally you would be good - theoretically!

Let me get on my fire resistant suit and here comes the flames in 3 . . . 2 . . . 1 . . .

Cheers

Jim

 

[artieb]

That's exactly what I'm thinking, Jim

 

[gearhead1]

I think it would be very difficult to keep them in sync without a sophisticated control mechanism.

 

[micromind]

Are the 2 gens connected to the same engine?

What about voltage regulation? AVR or capacitor?

 

[artieb]

Both generators are mechanically locked, and always the same rpm

 

[N_Jay]

Both generators are mechanically locked, and always the same rpm

That is the only way, you still have a little work to do to make sure they are locked perfectly in phase.

 

[nadogail]

No idea how you could sync them up without buying equipment that would be more expensive than a 20k generator. For units that can be paired (only inverters, AFAIK), the systems are built in.

Light Bulbs can be used to indicate when the generators are in synchronization with each other, the Governor on the prime movers will need to keep the generators in sync once synchronization is achieved.

I remember reading about this in one of my father's Audel's engineering books, back in the 1950's

 

[cycle61]

If you don’t already know how to do this, the answer is no. If you do know how to do it and you’re just waiting for somebody to tell you it’s an OK idea, why are you even asking?

I’m an electrical engineer. There are a couple different ways to do this, but they’re all some combination of sketchy, illegal, and/or expensive, and none of them are anything I would want near my house or shop.

 

[N_Jay]

You need far more than the governor to hold phase on 1 phase generators.
Three phase will keep themselves in phase

That is why they were able to manually phase power plant generators with little more than a light bulb.

 

[Firebrick43]

what is an oscilloscope?

maybe give HF a call and see if the generator that you have can be parallel together.

their manual for the 9500Watt inverter generator says you can get a parallel kit.

https://manuals.harborfreight.com/manuals/59000-59999/59188-193175459091.pdf

He doesn't have an inverter generator, nothing remotely similar.

No, you're not going to be able to sync them. Even trying to set one as leading and one as lagging won't do anything as a decent size load bogging the engines down would throw them out of sync.

The sync and lock in big generators all the time, some times 10 or 20 or more in data center back gens and third world power generation. Most of the stuff is computerized now but at one time it was all brought online one at a time and synced/locked in by hand.

as one engine bogs then the weaker one (just slightly as the generators cant be different in output) will start taking some of the load, they cog together and would be very hard to put a load that would make them go out of sync unless the load would trip the breakers anyways.

They sync them with a syncscope or even a 240 lightbulb as shown here.

Probably still not a good idea for the average individual, to easy to let the smoke out.

 

[micromind]

Since the 2 gens are mechanically connected together, it's important that the shafts are positioned exactly together. If one is either ahead or behind the other, they won't synch together.

If they're 240 2 wire, ensure that the frames are not electrically connected together then run both at speed and measure voltage from L1 on one gen to L1 on the other using something other than a basic multimeter. If you put some sort of a 240 load on L1 and L1, you can use any meter.

If the voltage is zero, connect both L1 leads together.

Do the same thing with the L2 leads. If no voltage, they're in synch. If 240, shut them down and rotate one of the shafts 180º. Test again.

With the L1s connected together, if there's less that 240, you'll need to rotate one of the shafts a little for a small voltage, more for a larger voltage. If rotating one shaft results in more voltage, it was turned the wrong way.

Once you get them in synch, they'll stay in synch.

If the gens are 120/240, it's a bit more complicated but can still be done.

 

[N_Jay]

The military gensets in the video are 3 phase.

I have give it some thought, but I would still be careful with single phase.

Will a single phase generator run as a motor without slipping out of phase? (Run synchronous)?

 

[micromind]

The military gensets in the video are 3 phase.

I have give it some thought, but I would still be careful with single phase.

Will a single phase generator run as a motor without slipping out of phase? (Run synchronous)?

They will.

Years ago, I paralleled 2 small single phase gens together, one was a 5KW, the other was smaller. This was needed to start a 3HP air compressor. If one of them ran out of gas, the other would motor the engine but of course, lug it a bit. But they stayed in synch.

 

[ihateminimumwage]

The sync and lock in big generators all the time, some times 10 or 20 or more in data center back gens and third world power generation. Most of the stuff is computerized now but at one time it was all brought online one at a time and synced/locked in by hand.

as one engine bogs then the weaker one (just slightly as the generators cant be different in output) will start taking some of the load, they cog together and would be very hard to put a load that would make them go out of sync unless the load would trip the breakers anyways.

Probably still not a good idea for the average individual, to easy to let the smoke out.

I've worked jobs with 9x 1.5meg gens synching in and the taking over grid power. Just commenting on trying to sync up HF gens.

 

[Firebrick43]

I've worked jobs with 9x 1.5meg gens synching in and the taking over grid power. Just commenting on trying to sync up HF gens.

I am no fan of Horror Fright but to the question of if it can be done, the answer is yes with those gen heads the OP has. I don’t see what being sold at HF has anything to do with them being locked and staying in sync.


Now it’s very debatable on the question of should it be done?