Linking two gens together?

[Henry W]

With all this trouble why not just buy a larger generator to meet your requirements? And when the need it not there than use the smaller generator.

Henry

[vdubnut62]

With all this trouble why not just buy a larger generator to meet your requirements? And when the need it not there than use the smaller generator.

Henry

That's what everybody else (rational people) would do.
Now where's the fun in being a Lemming?
Ron

[rl71459]

The Light bulb trick.

With the neutrals of 2 different AC power sources connected together. and one light bulb lead connected to one power sources hot leg and the other connected to the other sources hot leg the bulb('s) are indicating phase synchronization. When the Bulb('s) go out the 2 sources are in sync at that time.

By adjusting the speed (Hz's) of one of the sources (Generator) you should be able to maximize the "Bulb Out" time. This allows the biggest window for closing a contactor while in phase.

Note: The Bulb('s) will be powered at the sum of the 2 power sources. Often 2 bulbs will be connected in series to allow for the "Double Voltage" when using typical "Incandesent Bulb's" Some bulb's are rated for a high enough voltage and can be used directly... No second bulb required.

Rob

[Henry W]

With all this trouble why not just buy a larger generator to meet your requirements? And when the need it not there than use the smaller generator.

Henry

That's what everybody else (rational people) would do.
Now where's the fun in being a Lemming?
Ron

Ok,I guess.

[mobile_bob]

then there is always the possibility that one of the two bulbs burns out, then what?

very real possibility of a train wreck, unless you are very lucky.

i ain't that lucky

probably better use neon bulbs or something better than off the shelf incandecent bulbs.

or find a surplus syncroscope, or...

use an induction generator as the secondary unit, or...

use a bigger generator when you need it.

somehow i am not wanting to be the first guy to try syncing two harbor freight generators, or an st with an expensive
inverter, or even a gennie and a cheap inverter.

maybe two st heads that are belt driven with the drive belts loose on one unit so that i can grit my teeth and pull the lever
without fear of something very exciting happening.

then there is the use of a small fuse while in the testing phase, simply fuse one unit with a fuse maybe 1/10th the capacity of the
unit to be bought on line, that way maybe it blows as the weaker link if you are not in sync, and use it until you are comfortable with the results.

the fuse method is one that i frequently use when paralleling connections on transformers and generator connections, when i am unsure of phaseing, a small fuse will blow if i am 180 out and saves me from a potentially damaging event, like dirty undershorts.

fwiw

bob g

bob g

[rl71459]

I was only explaining how the bulb trick works.

This should NOT! be seen as a recomendation! Phase Syncing Power sources is best left to the Pro's.

I would never recomend doing this at home! Many Dangers are Present!

Rob

[Crofter]

I have been party to a few occasions of swapping over a pair of 200KW generators "on the fly" using the light bulb.  It did not give me a sense of tranquility being in that building with that old Caterpiller and a screaming Jimmy and being about to hand breed them.

I didn't see it tried but was told they would osccillate back and forth rather than share the load.

Mentioning having the neutrals tied makes me think you would want to be danged sure you had two generators with identical voltage,frequency, phasing, and connection schemes as well as neutral bonding methods. I have had just enough to do with it to make me very leery of the proposition.

[Ronmar]

Two separated generators will rarely stay perfectly in step for very long.  Ie: the lightbulbs will stay lit more than they are dark.  If you are getting no light at all, your light circuit is probably bad.  You can always use more than two light circuits in parallel.  You need to use incandescent lights so you can see the filament.
Last ship I was on had 3 main diesel gens.  We always ran with 2 in parallel, but different ops,  maintenance and cooling issues when crossing the equator, we were always shifting power, sometimes several times a day.  It is really not that difficult, you just need to understand the process and what you are looking at.

[rl71459]

Watch This

www.youtube.com/watch?v=FyJdojJJSFY

It's not anyone I know!

Rob

[Ronmar]

Watch This

www.youtube.com/watch?v=FyJdojJJSFY

It's not anyone I know!

Rob

I think that is from across the pond as it has what appears to be a volvox exhaust heatex mounted on the wall. (edit  Duh, I just read the username who posted it volvoxltd...)  But it is just that easy. Be sure to read the description that goes along with it..  While watching that one, I saw this one down in the related videos bar along the right  It is a video taped of what appears to be a computer slideshow of the process with a 3 phase generator which also explaines phase missmatch.  It is quick, so i had to pause it to read the information...  

http://www.youtube.com/watch?v=JGjZLqR2Jf8&feature=related

[BioHazard]

With all this trouble why not just buy a larger generator to meet your requirements? And when the need it not there than use the smaller generator.

Henry

If nobody ever tried to do things different, I guess this website wouldn't exist would it?  I only ask mainly out of curiosity, but, I am interested in coming up with a way for my little 800w generator to make 1200-1500 for a few minutes.

The idea of multiple small generators is actually quite common and useful in the "RV" crowd, with the little Honda inverter generators. They can easily be paralleled from the factory, so you can have the full 30 amps your RV wants. I know it's a popular option because I have personally manufactured and sold thousands of parallel cable kits for these generators. I would never pay what Honda is asking for TWO generators...but I like the concept...

So nobody knows if a grid tie inverter can tie into a generator?

[Crofter]

If the generator in question can produce power that is clean enough in waveform, frequency, voltage etc. to meet the grid tie inverters sampling approval procedure it should connect, but what purpose? charge batteries. Any load that pulls the generator even momentarily outside of limits is an autmatic disconnect, wait period, resample etc.

[BioHazard]

If the generator in question can produce power that is clean enough in waveform, frequency, voltage etc. to meet the grid tie inverters sampling approval procedure it should connect, but what purpose? charge batteries. Any load that pulls the generator even momentarily outside of limits is an autmatic disconnect, wait period, resample etc.

That makes sense, I was thinking more how the induction motors lock onto the same frequency once connected. Is there any such inverter that could do that? Or maybe some way to disable the automatic shutdown, since there is no real grid?

[Ronmar]

Well if you want this for backup power, it could probably be done with a regular inverter, 800W inverter paralleled with 800W generator?  It would have to be a sine wave inverter to match up with the sine wave of the generator.  The issue I suppose would be load sharing.  I am not sure how the inverter would handle having power fed back into it if the generator took the lead:)  That would be an unusual rig for sure...

[vdubnut62]

With all this trouble why not just buy a larger generator to meet your requirements? And when the need it not there than use the smaller generator.

Henry

That's what everybody else (rational people) would do.
Now where's the fun in being a Lemming?
Ron

Hey don't take me too seriously, just trying to stir up things up a little.
Ron

Ok,I guess.