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Small Cabin Forum / Off-Grid Living / Generator 220 plug again
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paulz
Member
# Posted: 21 Aug 2020 10:57am
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I am wiring a new 4 prong outlet to my generator that had an odd 3 pronger, the two hots and a ground to the chassis. The new outlet is like this one, and I am wondering if I should add the neutral wire at top to the middle of the paired windings as shown that make the serial 220 output. I don't think any of my compressors or pumps use 4 wires, and the 3rd is probably a ground on them. Last thing I want is to burn up the windings by adding this wire.
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Brettny
Member
# Posted: 21 Aug 2020 11:16am
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Compressors or pumps usualy only need 240v if they are 240v. The neutral is usualy only needed on items like a stove that would also have 120v and 240v things in it.

paulz
Member
# Posted: 21 Aug 2020 11:33am - Edited by: paulz
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That's right, these outlets can be used for 120 stuff that has the right plug can't they? The genny has a separate 120 standard house type outlet so I doubt I would ever need the neutral then.

Thanks Brett

Brettny
Member
# Posted: 21 Aug 2020 03:00pm
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120v needs a neutral.

toyota_mdt_tech
Member
# Posted: 21 Aug 2020 09:54pm
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except on a generator.

paulz
Member
# Posted: 23 Aug 2020 06:58pm - Edited by: paulz
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Long boring story ahead..

So, today I finally powered my compressor with the generator from hell.. but not without some grinding.

To recap, I a few months ago I went to a moving sale to buy a tool box for my new shop. They had a compressor there, 6.5kw, 13 hp Honda, 100 bucks, not putting out any juice. I figure I've gotten a couple of my other smaller gennys working again cheaply with new capacitors, brushes, regulator etc. so I buy it.

Get it home, open it up..oddly, no regulator, no brushes. But it has a capacitor, so I bought a new one. Didn't help. Tried flashing it with drills, a battery.. nothing. Scour the internet for a wiring diagram, nothing, company out of business. Thought about giving up, but the kicker is this Honda engine starts first pull every time, runs like a top.

Then, not more than a week after buying it, a neighbor at my cabin calls and says he's moving, asks if I want another generator, diesel, electric start, 6.5kw, free! Lost the key he says (yes has an ignition key, or did). So I grab that, bypass the key switch, works like a champ.

Still wanted to get the gas one going, save the diesel for long term power or something, it doesn't seem like the type of generator you would use to power a table saw or compressor for a few minutes. So I finally found a guy that repairs generators, paid him $50 to have a look. Right away he sees the resistors in the rotor are blown, little round blue things, now with big brown holes in them. He was pretty sure that was all it was. They are not actually resistors, they are varistors, a type of resistor that limits voltage, takes the place of the regulator in this genny. Order them online, pack of 20 for about 5 bucks.

I solder two new ones in the rotor, put it back together. Success, full power at the stator! So I put it all back together, fire it up, immediately blew the varistors again. Damn. A couple weeks went by, I got bored enough to take it apart again and solder in two new varistors. Worked again thank goodness, but this time I wanted to make sure the wiring was right. There was a tag on the generator from some repair shop, they must have monkeyed with the wiring trying to fix it.

After much studying, I got the hang of the wiring, which is pretty simple once you understand it. The stator has two windings, each put out 120v. They run to a 120/240 toggle switch. In 120 mode, the windings are in parallel, so both windings share and double the load capability. Flip the switch the other way, the widings are in series to make the 240v. Sounds simple but the switch wiring is a bit tricky, and the windings have to be paired in the correct direction or no soap.

Anyway, rewired the thing and got it working at the sockets. But it had this odd 240 socket, looked like a 120 socket with the slots turned sideways. So I ordered a 'Generator 240 socket', the round 4 prong ones like the diesel generator has, and also fits my compressor.

Got that installed yesterday, today was the big day to try 240v (the 120 works fine). Go to plug the compressor in the new socket, the L on the ground lug goes inward, the one on the diesel (and the compressor), goes outward! Crap!!! Why do they do this! Well I really wanted to test, so I ground the leg off the L and it fit. And it worked. The ground lug is longer than the other 3 so it's easy to tell, but I know it ain't right..

So, hopefully I get some good use out of this thing in my shop. End of story, again, hopefully.
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toyota_mdt_tech
Member
# Posted: 24 Aug 2020 08:19am
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That ground lug pointing different direction is usually a different amp rating, I think you have a 20 and a 30 amp, there is a small number on the outlet like an L14-30R etc. Maybe you had an L14-20R on one and the 30 on the other.

Brettny
Member
# Posted: 24 Aug 2020 09:58am
Reply 


Toyota is right the two sideways plugs usualy is a higher amp 240v plug. I'm sure google has a image of all the dif plug types and what voltage/amp. I'm thinking that's a 240/30a. It's not a very standard plug on generators. If you can switch it out for the one you bough I would. That looks more like the standard 240v30a twist lock like on a generator.

With the series/parallel switch you have on that generator can you get 120v and 240v out of the same plug? I would not run that generator without a ground.

paulz
Member
# Posted: 24 Aug 2020 03:05pm
Reply 


Yep, the inny socket is a 30a, the outy is 20a. Remember that, it will be on the test later.

I don't know about using the 240 socket for 120, there is a dedicated 120 socket. The toggle switch goes from one socket to the other.

toyota_mdt_tech
Member
# Posted: 24 Aug 2020 03:40pm
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My big Honda EU6500is has a 240VAC switch also.

I use it to run my entire house so leave it in the 240 mode.

Brettny
Member
# Posted: 24 Aug 2020 03:49pm
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But I bet the eu6500 has a 4 prong 240v plug?

paulz
Member
# Posted: 24 Aug 2020 03:59pm
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From what I read, the 120/240 generators that don't have a switch just use one winding for the 120 socket, halving the capacity. Or they have 2 120 sockets with one winding going to each, so you get full capacity if using both at the same time.

toyota_mdt_tech
Member
# Posted: 24 Aug 2020 08:27pm
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Quoting: Brettny
But I bet the eu6500 has a 4 prong 240v plug?


Yes, its the L14-30R

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