Stacking or Paralleling Inverters????

I've seen inverters in parallel, and yes, they simply used the same sync line. But they were designed to work that way. I'd be very careful if I were going to hack a couple of commercial units.

Of course, it will void the warranty. They didn't want to talk to you because of the liability problems if they let you even _think_ they'd approve such an arrangement.

Open the units, take a look, and if you have the electronics background to do it safely, then do it, otherwise, leave them intact, sell them, and buy a bigger unit. If they have "Warranty Void if This Sticker is Removed" stickers, then be aware that they're extremely difficult to remove without it showing.

Good Luck! Rich

Don't even bother THINKING about doing something like this. Buy a bigger inverter.

I agree. If you don't know why this is impractical except for a very experienced engineer, you can't do it. However, the services of an experienced engineer, like myself will cost more than a bigger inverter.

If you don't care about hosing the inverters, why not try? If you could tap the clock output on one, disable the clock on the other and bring the signal over, It could possibly work. As you say, phasing could be an issue. The clock signal may be high since many things go on inside the inverter in a nornal 60 Hz cycle. Some units adjust the output pulse width for regulation. getting all this in sync could be a problem. John

On Thu, 29 Jul 2004 14:51:49 -0400, J Poy put forth the notion that...

The solution is simple... sell the two 400 watt units, and buy an 800 watt unit. You're not going to be able to get two of them to stay in sync.

We did it all the time at Electro Solids corp. But our inverters had inputs for syncing them together. If you want to do that, get inverters with syncing ability. But unless the converters are short circuit protected with the voltage falling off into a short rather than just turning off do not parrelel converts.

What will happen when you parrellel converters is the one with the hightest output voltage will carry as much of the load as it can and then go into overload so the voltage will fall till it matches the output voltage of the one in over load and then it will take up the remainder of the load.

If the two converters are synced, it is better to put the outputs in series with each supplying 1/2 the load. voltage. You can put both in series and use a step down tranformer to accomplish the same thing.

But in general, I would say, if you have to ask, you should not do it as you just do not understand what is involved.

We did it all the time at ElectoSolids Corp.

But, as you said in your earlier post, your units were made to do that. This is just not a do-it-yourself, hobbyist undertaking. Without the proper experience (doesn't have it), full schematics (doesn't have them), lots of test equipment (meters, scopes, etc. - if he has all that, he should be able to afford an 800kva inverter, they're a lot less expensive than a trip to the emergency room), and more than a little careless disregard for safety (both his and whoever winds up using this contraption), this is better left alone.

Al

bushbadee wrote:

I agree with you completely. And I basically so stated. I just told him that it could be done and that it has been done.

But I also said and have often said this, if you have to ask how to do it, then you shouldn't try to do it.

When fooling around with 400 and 800 va inverters which can give you a quick trip to the cemetary, that holds double true.

engineering

oops, I meant 800va, not 800kva.

Alan Stiver, PE wrote: ... he should be able to afford an 800kva inverter, they're a lot less

Hi everyone!

Thought I'd let you know what I decided to do:

... Without a schematic well it's like going on a trip without a map, if you know what I mean. You can get there but might take you along time. I hoping someone might have a schematic of this inverter. ... Your all right with regards to the dangers of trying to actually parallel two of these inverters, but I really wanted to hear someone who might have actually done this with these particular ones. ... My background is in electronics, but as I see it why try to invent the wheel if someone has already done it. I am not working on inverters per say, but I do have a electronics degree and have study inverters in the past. ... Yes I do have all the electronic (Scope, DVM, generators etc.) equipment to perform the work safely to the inverters as well to me.

In the end I have decided to hold off for now and try to more research on the subject.

Thank you all for your comments!

Jim

Real inverters is a very specialized subject that they do not teach in Colleges. The secrets were passed passed on to me by a German scientist.