Connecting 4 gas 2.5kw generators in parallel

[Renex]

I am interested in knowing if anyone out there knows of a company that sells a kit to connect 4 gas powered 2.5 kw generators in parallel.

Thanks in advance.

 

[rbulsara]

I would start at the generator manufacturer, if these are existing units.

I may be out on the limb here but you may not find such a gizmo, becuase the such small generator may not have sophisticated governor and voltage regulator for parallleing function.

Just curious why do you want to do this?

 

[Renex]

We have a number of these small generators allready 20 - 30 and they are all different makes and models. Each on it's own is to small to power a house - but in a hurricane or disaster we could power 7 or 8 homes in a neighborhood and at least people could prepare meals get a warm shower etc... It is something a number of us have discussed in my neigborhood. We live in Halifax NS and while we got away last year without a problem the year before we where hit directly with a cat 3 hurricane.

 

[mpparent]

rbulsara is right...

Those small units are not going to have the ability to do that, and I'm highly doubtful a gen. manufacturer will have something to do this. In addition, you say that the sets are different makes, etc. Typically when you parallel gen's you want them to match up as much as possible, although, these days, you can get regulators/governors to handle the issues associated with unmatched sets.

Mike

 

[TheBlacksmith]

Anything is possible, but I suspect the cost would exceed that of buying much larger 7.5 to 10 KW units, especially if you can sell the smaller units for a reasonable cost. It would require (1) all the units to have the same governor and voltage regulator, set to the same percentage "droop", or (2) an active compensation system that involves data exchange to/from each unit.

Blacksmith

 

[itsmoked]

Guys are you suuuuure this won't work? Be fun as heck to try it.

The reason I think it *could* work is that unlike the big machines, you all work with constantly, these small machines have almost no inertia. I would think that crummy govenors could almost be trumped by the network. The engines would just drive the generators up against the network and not be able to push out of sync. Just a thought.

One big one would be nice with propane. Though certainly less redundant.

 

[ccjersey]

Sounds about like herding cats!

Honda makes a paralleling rig for TWO of it's small generators.

 

[itsmoked]

Those are inverter derived gens ccjersey. Very nice ones at that! All portables should be that type. They have a nice system that links the reference frequencies.

 

[ccjersey]

I would not underestimate the good someone without power can get from a 2.5kW generator (or two). Of course fuel quickly becomes the next problem in an extended outage.

The inverter based technology is interesting. The Honeywell Parallon generators seemed to me to be a great idea, but they are no longer made (or supported?) I believe. There must be a place for turbine prime movers, and the inverter replacing the geartrain as a method of eliminating the gap between the turbine rpm and the typical alternator rpm seems perfect.

does anyone now if the hondas vary the engine speed to respond to load variations or do they run close to synchronous speed?

 

[itsmoked]

The Honda's run in a pure energy management mode. The engine runs at the speed required to produce the energy required and no faster. These generators run at all sorts of speeds. As you add load they speed up accordingly. That's why they can run 10 hours on a tank.

I would prefer propane because it doesn't rot or clog up the carburetor waiting to serve you. You can order a propane conversion kit for these or any small generator for that matter.

http://www.propanecarbs.com/

http://www.propane-generators.com/

 

[ruggedscot]

Hmmm forget doing it by syncornisation - how about putting the outputs through a rectifier and then using an invertor to give you your ac ?

need to watch for spikes and all sort of nasties.

rugged

 

[itsmoked]

ruggedscot; When paralleling AC generators you must always synchronize them before throwing the switch or...KABLOWIE.

The DC method certainly avoids the entire hassle of synchronizing but has its own problem. Namely "load sharing". When you hook DC generators together they can have problems sharing the load. Since they won't all have the exact same source impedance they won't evenly share the load. One will hog it all the others may provide none. The second problem is, the inverter would cost a fortune. Inverters above 1kW are pricey. That's why the above Hondas cost $2K; $1k for the generator $1K for the inverter. Inverters cost about $1k per 1kW once you get over 1kW.

 

[itsmoked]

BTW Someone might know of a way to get the DC method to work. I'd like to hear it.