# Help with generator issue



## STS (Dec 28, 2013)

Hello,

I have a 8000 running watts B&S generator that has been serving us well up until recently, when after 3 days of use I lost one of the 120v wires on the 4-prong connector. Not very knowledgeable of the proper terms, so bare with me 

There is a 4-prong plug on the generator that supplies 240v (two 120v, one neutral and one ground). One of the 120v lines now has no power. All of the 120v plugs on the generator work just fine. No tripped breakers either. A neighbor who is a commercial electrician unplugged the generator panel and tested directly at the wire coming from the alternator and said that the problem is not in the panel but with the alternator. 

After much reading, I tested the voltage regulator: plugged a 12v battery to the brushes, started the generator and tested the voltage regulator and it gave me 120v. According to what I read, this means that the problem is in the voltage regulator, not the alternator parts. 

I have two questions:

1. Does it make sense to someone with more experience that a bad voltage regulator would only produce 120v on just one of the wires, instead of both at 120v each at the 4-prong plug?

2. There is something called a booster or some such (a small electrical board with black covering, like a tube) which connects before the voltage regulator. There is no parts number or even a mention of it in the B&S parts list diagram and I have seen on videos that some people just bypass that booster and hook directly to the voltage regulator. Could this "booster" be the culprit? Can I just bypass it and see if it would fix the problem? I have no idea of its purpose, so I figured I ask first. 

Thanks a lot!


----------



## aandpdan (Oct 8, 2012)

Depending upon how your generator is wired it could be a failed winding in the stator. 

It seems odd that all the receptacles are working correctly. Most generators will split a receptacle so that the loads balance - you wouldn't be drawing 120v off of just one winding but divide it amongst both.

What model number is your generator? Do you have a wiring diagram?


----------



## STS (Dec 28, 2013)

> Depending upon how your generator is wired it could be a failed winding in the stator.


But if it's the stator issue, should the voltage regulator test I described earlier show any power at all? Form the videos I've seen, if the test shows no power, then the problem is with the alternator and if there is power - the alternator is fine. Just want to make sure.



> It seems odd that all the receptacles are working correctly. Most generators will split a receptacle so that the loads balance - you wouldn't be drawing 120v off of just one winding but divide it amongst both.


So basically it could be just a bad wire on the 240v connector on the panel? The wire that comes from the alternator to the panel has 6 wires, I have no idea how I should test this to make sure it's working properly, I just go by what my neighbor said. He could be mistaken. 



> What model number is your generator? Do you have a wiring diagram?


The model number is 030426 I haven't been able to find a wiring diagram, just a parts list with diagrams for the alternator and the generator.


----------



## STS (Dec 28, 2013)

Ok, it seems that this could be the right wiring diagram, to bad I can't read it 

https://www.partstree.com/parts/?lc=briggs_and_stratton_power&mn=030426-0+8%2C000+Watt&dn=5402

There is a full view here: http://images.partstree.com/?l=briggs_and_stratton_power&p=images\47\21\0013&nd=0&z=30


----------



## STS (Dec 28, 2013)

Ok, if you look at the wiring diagram, the connector of the alternator is in the middle and five actual wires come out of it - 0, 11, 22, 33 and 44. I am sure you know this, but I am just recapping what I understand  

I tested the connector by plugging in the black wire of the volt tester into "0", which I assume is negative? ground? and then the red wire to all 11, 22, 33 and 44 and they all read 60v. Is this normal? Adding them will equal to 240v, but not really sure if this is how it works (total noob past wiring a light switch)


----------



## aandpdan (Oct 8, 2012)

Don't worry about the readings you got. Wire "0" is ground. I suspect you are reading phantom voltages with your meter (it was digital right?) as it really should read nothing.

See the note: "tab must be broken" right there that tells me that the receptacles are wired as I stated earlier, split. The top is on one leg and the bottom the other.

If ALL of the 120 vac receptacles are working then the generator is working fine and capable of producing 240 vac.

22 and 33 are the neutral (there is no "negative" in alternating current) and they are tied together. 11 and 44 are "hot" or the "line" one for each leg. From wires 11 to 33 you should have 120 vac. From wires 44 to 22 you also should have 120 vac. Checking at the outlets is fine. You say you had 120 vac to all so these are OK.

The problem seems to be at CB1 (circuit breaker).

On the bottom where it says "line" it taps off to feed the 120 vac circuit breakers CB2 and CB3 - so you are getting power to CB1. You say one side of the 30 amp receptacle TLR1 is showing 120 vac, so you have one good hot. There is a very good chance that CB1 has failed internally. It happens, alot, on generators. If you weren't getting power to the "line" terminals some of the 120 vac outlets wouldn't work.

From pins 2 and 4 on CB1 you should read 240 vac with the generator running. If you aren't check pins 1 and 3. Again, you should read 240 there and if you are, CB1 is bad.

Hope I explained it well.


----------



## STS (Dec 28, 2013)

aandpdan said:


> Don't worry about the readings you got. Wire "0" is ground. I suspect you are reading phantom voltages with your meter (it was digital right?) as it really should read nothing.
> 
> See the note: "tab must be broken" right there that tells me that the receptacles are wired as I stated earlier, split. The top is on one leg and the bottom the other.
> 
> ...


Thank you very much for your detailed explanation. I believe I understood everything 

As a side note, after thinking a bit and looking at the diagram and how the 4-wire plug is, I tested the actual plug coming from the alternator in a different way:

plugged the black wire in the 22 and the red wire in the 44 and it gave me 120v, but when I plugged the red wire into 11 - there was nothing. Shouldn't there be 120v coming out of 11 from the alternator? 
When I test TRL1 I get 120v on 44 but nothing on 11. If 11 is dead from the alternator, would it be possible for the regular receptacles (DB1 and DB2) to be getting all the power from 44?

Anyhow, I'm going to see if I could remove the panel and test the breakers as you described. Thanks again for all your help!


----------



## STS (Dec 28, 2013)

You were spot on the money!!!

Opened the panel and one side of the main breaker was melted and one of the wires was off 

THANK YOU SO VERY MUCH!!! You are the man!


----------



## aandpdan (Oct 8, 2012)

Glad to help.

As to the question about 22 and 44, those are one winding so you would read 120. When you tested from 22 to 11 you had a wire on each winding - with the connector disconnected they are isolated. 22 and 33 (the neutral for 11) would only be joined when the connection is made, so it should read 0.


----------

