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That is how it is now Browse,

I have Qty-2 120V 15A circuits that can also be accessed as Qty-1 240VAC 15A.

What I need is Qty-1 120V 30A circuit.
OK...so you need to parallel the two outputs for 30A (sort of like the bottom diagram on my generator):


Not sure you can easily do this since they are out of phase. See this thread:
 

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Discussion Starter · #22 ·
Hi Browse

Yes, like the lower picture. I've read that thread you referenced and I even started a conversation with cpotter to see if he was successful but alas, he does not answer.

I understand swapping the windings from series to parallel but the extra connections that go to the AVR are confusing me. I labelled them B and D in the diagram and picture.

Is it possible that the voltage detect for this generator is low?
 

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Discussion Starter · #23 ·
So I did a little digging and I've found that my generator portion was made by SawaFuji, they apparently made a lot of generator heads for Homelite, Kubota Wacker Neuson and even Honda. I'll try to find a service manual for one of those since I can't find one for the Homelite.

I also did an experiment with the AVR. I fed it 12V into the yellow wires and hooked a light bulb across the field wires that go to the brushes. The light bulb lights but as I raised the voltage on the sense wires (blue and brown) the light goes out at 18VAC. That's quite low and explains why my gen has the extra windings. A lot of AVRs sense directly off the 120VAC output but that means they are using high value resistors to divide down the sense voltage to a manageable level and high value resistors are more prone to drifting and going open. I suspect that the extra winding was so that the AVR could be built for low voltage sensing and therefore be more stable and have less failures.
 

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Discussion Starter · #24 ·
I've pulled the wiring apart to separate the lower two windings then I inverted each and joined them in parallel with the uppers. See picture. This will double my current and make it a 120VAC only generator.

Here's a question I have. B and C are connected and fed to the AVR, Their corresponding point on the second winding is H and E. Do I tie all four together (BCHE) or leave them separate?

The problem with this configuration is that the voltage to the AVR is now half of what it used to be so I'll either have to modify the existing AVR or build a new one that cuts off the field current at 9VAC (instead of 18). It shouldn't bee too difficult, I build regulators for alternators all the time, I'll make it adjustable while I'm in there. The hardest part will be digging the potting/epoxy out of the box to get to the board.
9184
 

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I've pulled the wiring apart to separate the lower two windings then I inverted each and joined them in parallel with the uppers. See picture. This will double my current and make it a 120VAC only generator.

Here's a question I have. B and C are connected and fed to the AVR, Their corresponding point on the second winding is H and E. Do I tie all four together (BCHE) or leave them separate?

The problem with this configuration is that the voltage to the AVR is now half of what it used to be so I'll either have to modify the existing AVR or build a new one that cuts off the field current at 9VAC (instead of 18). It shouldn't bee too difficult, I build regulators for alternators all the time, I'll make it adjustable while I'm in there. The hardest part will be digging the potting/epoxy out of the box to get to the board. View attachment 9184
Seems like you have your work cut out for you. If it does end up working, just make sure your new internal wiring can handle the increased current.
 

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What I need is Qty-1 120V 30A circuit.
As I mentioned WAAAAY back in post #2, this is kinda a snipe hunt... If you need 30A of in-phase 120V from a single outlet, this is not the generator for you...
 

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Discussion Starter · #27 ·
I don't know why you think this Tabora, I've found that this same 3800-US (160982) SawaFuji generator head is used on Honda, Kubota and WackerNeuson generators to do exactly that - 120V at 30A. It's rated for that and when configured correctly has no trouble producing it.
 

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hey jayarr do you have a wacker model number?
or an exact honda number?
I have older prints for both of those brands
 

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Discussion Starter · #29 · (Edited)
I've looked at so many my memory is a little fuzzy but I think the Wacker Neuson was either GP3800A or GV3800A.

I've found all of these manuals online.

BTW, I found engineering reference regarding tying my tap points together and the answer is no, you leave them separate. I found several other generators where the voltage detect was from one leg only. So I'm leaving B/C and H/E separate.
 

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120V at 30A
It does give 30A of 120V (on two outlets) or 15A of 240V. But you have to invert one of the legs in order to get it in parallel on a single 120V outlet. You can buy that capacity very reasonably in a used genset without the shenanigans of phase inversion.
 

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Discussion Starter · #31 ·
Yes but you know that to invert that second phase all you need to do is swap the right pair of wires right? All I wanted was help figuring out which wires to swap. Instead you tell me to buy a different generator. Did you really think I would read your post, go throw this one in the trash and head out and buy a different one? I just don't understand what you thought that post would actually solve.

I already own this generator - I worked hard, earned some money and purchased it - solutions that begin with "you should buy this different model" aren't very useful to me, I don't have enough money to abandon this generator and buy a different one.

I came here for help not judgement, maybe I shouldn't have.
 

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Yes but you know that to invert that second phase all you need to do is swap the right pair of wires right?
Best of luck to you. A lot of people have asked how to do this, but I don't believe anyone ever succeeded. Some let out the secret smoke. If you do succeed, I hope you post the solution for posterity!
 

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To me seems that is better to find a modern replacement, quiter, compact, reliable and more efficient. Some to look on different options.
 
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