Honda EU2000 Transformer Problem

Wire a death box (quad box, metal cover) into the center of a 12ga, 25' ext cord. In the death box, place a duplex outlet, in series with the hot wire only. Wire a incandescent rated wall switch across the outlet. Switch off.
Plug in a 250W heat lamp & turn it's switch on. Start the generator, and plug in the death box cord. Plug the PSX-240 into the ext cord from the death box. Switch on the genset CB. The light bulb limits the power in the circuit till the core charges up (about 3 seconds maybe) Turn the death box switch to ON, bypassing the light bulb, and you should be good at 1.8Kw.

This could all be hardwired after proven out, with a NO relay and a push-button switch) Change the light bulb wattage as needed (500w worklight)

Mike, I've tried everything from light bulbs to a really long cord to even a run capacitor out of a single phase motor. I haven't been able to come up with a "poor man's soft start" yet that works.

I can fix you up. There are a few ways to getter done depending on how much time and money you want to spend. Easiest way is just to get a transformer that matches the source impedance.

Option one is to use what is called a Inrush Current Limiter circuit. Sound fancy and complicated but very simple. All it amounts to is a temperature dependent resistor with a Negative Temperature Coefficient, and a relay to short it out after one second. When you initially apply power the resistance is high enough to start the saturation process. As current flows the resistor heats up and the resistance goes lower and lower fully saturating the core. Than about after one second you have a relay short it out thus removing it from the circuit and off you go.

Sunking - yeah, that would be like a typical soft start box for a big three-phase motor that starts under load. Without those soft-starts factories and plants that run big motors would cause brown-outs across entire neighborhoods when they fire 'em up.

Now, I just have to figure out what commonly available stuff I can build a little one out of

I had a 300uF run capacitor in the shop out of a single phase motor and tried that but it didn't even act like I had the capacitor inline. The reason the conventional generator can "soft start" that transformer is because when the core magnetizes, the corresponding voltage drop you get with a conventional generator limits the current so it just gently brings the transformer online (although the transformer still makes a big "thud" when it fires up). The inverter genset has virtually no surge power at all compared to a conventional generator. It's DC input is fed by a tiny little three-phase permanent magnet generator on the engine crankshaft that's rectified output, and that little generator and engine doesn't have anywhere near the surge capacity of a battery to keep within the inverter's operating limits. So it faults and shuts down.

I'll have to go to the local electric motor rewinding shop (about a 60 mile drive) tomorrow and see if I can find a suitable resistor and timed contactor out of a junked out soft start. The trouble is, those resistors in even a small soft start for a three-phase motor are about 6" in diameter and 2 feet long and I doubt the little EU even puts out enough power to energize the contactor coil and close the contactor in one of those.

But maybe old Bob there at the motor shop has something laying around that will work - he usually does

I'm sure a 100w bulb is too small. Maybe 250w heat lamp is too small. But a 500W quartz work light should be enough to "fill up" the transformer in a couple seconds, without crashing the genset.
Inverters have trouble with large inductive / capacitive loads.

My Honeywell 2KW inverter genset, was running just this last weekend, for a couple 5 hour runs, driving a 3.5KVA step-up transformer I rigged up as an auto-transformer.

Maybe there is a fault in the transformer ? Try firing it up from another source and "bake it out" for a couple hours, in case some moisture got in there ?

If the transformer is good, I just can't see how it's not working with a light bulb as a ballast.

Mike, I think the transformer is OK. We brought it to our place because we thought there might be something wrong with it. We tested it on our EP2500CX and it worked fine. I measured the inrush with my Fluke and it's about 80-90 amps with the Fluke on high value capture. I verified that against our PSX-240 and got the same reading for inrush current.

I agree that a big light bulb should work. However, we have never had a use for a 500 watt quartz lamp here and it would be a 60 mile drive to get one

So we tried everything we had available at hand so far, including a long cord, and it didn't work. Today I have to run into town and then I'll see if I can find something to make a soft-start from.

Sunking - hey, the lightbulb came on over my head this morning when I re-read this. Your description is exactly how a soft start works - I just need the parts to build a little one for this tiny generator. So, I need a resistor. I got a 120V 2000 watt water heater element here. That heater measures 7.1 ohms. That should cause a pretty good voltage drop hooked in series on the hot leg going to the transformer to "soften" how fast the core builds a mag field around it. If one isn't enough I got two of 'em and can put 14 ohms in series.

I'm going to try this this morning with a light switch wired to bypass it like Mike's Death Box and see if it works. If it does, all I need is a timed 1 second delay contactor from the motor shop.

Thanks!

14 Ohms on a 120 volt circuit should be more than enough and limit start up current to around 9 amps. Might have to play with time settings to find the sweet spot but 1 to 2 seconds should getter done.

Just got back from the neighbor's place. One water heater element worked. But it make the generator grunt and the overload light flashed on for a brief instant before I flipped the switch. The transformer load is only about 10 watts once the core gets magnetized but the heater load is 2,000 watts which is all the little generator can put out on surge initially. Once I flip the switch the transformer is fired up and online and the heater is out of the circuit. And we got 240.6V at the inverter input.

The neighbor said forget the timed contactor. He has to manually start the little generator anyway, and he said he'll just throw the switch after it starts and that's no big deal.

Now I just have to build a nice box for him with the element mounted on an aluminum heat sink (the element does get pretty hot almost immediately before you can flip the switch) so it's safe and somewhat professional looking. A water heater element clamped in a vice and a switch dangling by some wires is not going to cut it long term........

Thanks guys!

Your Welcome.

Told you I could fix it.

Yeah, it's "fixed". I formed up a nice stainless steel box and made an aluminum heat sink for the element to mount on in it. I have to TIG the corners on the box and make a cover for it yet. I don't think there's much danger of him overheating the element if he forgets to throw the switch because the generator will only put out enough power to run that element in the circuit for maybe 10-15 seconds before it overload faults. So I'm not going to drill any ventilation holes in the box. He doesn't have a nice generator house like we got. His generators are in an old pole shed with dust and dirt and cobwebs and bugs and birds and stuff. Be good to keep dust and bugs out of the box.

Sounds like a good place for a fire.

Well, that's why I want to keep dust and bugs out of the box. If he forgets to throw the switch sometime and gets the element really hot at least it's contained inside the stainless steel box.

He's got a Perkins diesel generator in there sitting on a pallet with a piece of flex pipe going thru the wall for the exhaust. And now he's got a Honda EU2000 sitting on an old steel work table. And, of course, the rest of the shed is full of "stuff" too. Old boards that he cuts up for kindling for the fireplace. Couple old tractors. 1947 Chev truck cab sitting on a couple pallets. Several old rusted V-8 engines from the 60's and 70's sitting on their side on the dirt floor leaking oil out.

Yep. She's quite a place

don't get too fancy, the heater elements are going to fail from the thermal shock pretty quickly. I think the big light bulb as ballast, will be the better load.