Question about a generator

[amanda11270]

I have a generator that powers my house when the power goes out, I basically roll it out side, plug it into my house, flip off the main, fire up the generator, turn on the generator disconnect and everything I want to use in my house 240 or 120 volt works.

My question is not about this generator though. I own a bucket truck I use for my business, it has a real nice smooth running twin cylinder Kohler engine, and it has several 120 volts outlets all around it, and they all work fine. However, when I go to put my meter leads into the 120/240V outlet, I get the two individual 120 sides, but together they do not make 240V. I work as a technician doing HVAC, Electrical, Plumbing and have for 20 yrs. Whenever I had this symptom in a building, the building called an electrician and took care of whatever causes that missing 240v symptom. Anyone know what could be the reason my generator doesnt read 240V, it reads like almost zero on the hots together. Or is it supposed to be like this and im missing something, I see no switch to make it 120 or 240 volts. I havent tried to use the 240v with a load though yet. Anyone know more about generators, I never checked my whole house generator to verify it makes 240V total, but all the 240 stuff, AC, water heater works fine.

 

[Fast Orange]

Not all gensets are capable of 240 V-check the nameplate for the voltage rating.

 

[stangster]

Sounds like both 120V leads are on the same phase.

 

[KRB52]

Correct me if I'm wrong, but shouldn't checking across the two 120 leads (white and red) show a voltage of 0v? After all, there is no voltage difference between the two leads.

 

[stangster]

If they are on opposite phases they would read 240V

 

[amanda11270]

Its supposed to make 240V, its a 120/240 generator. It has two single pole 20 amp breakers on the generator itself, with outlets 120V outlets throughout the truck. Then back in the rear of the truck is a wired in 240V outlet box, with its own dual pole 20 Amp breaker on it. There must be something wrong with the windings or phasing I guess, that's a little beyond what I know about generators. I have so far only used it for 120V. I know quite a bit about adjusting this generator for Htz to make it run properly, the same generator runs the hydraulics for the boom via pump on the end of it, that is 95% percent of the time why I use it. That's a reason its hard to get to much on it to check windings etc, this pump blocks access to the cover for the windings wiring, voltage regulator, etc.

This was a former phone company truck, im sure the 240V outlet worked at one time, but even at the generator across the two 120s I do not get 240V. I had heard that it may need a load to actually make 240V, I didn't know if it was true or not though.

 

[wyliesdiesels]

Correct me if I'm wrong, but shouldn't checking across the two 120 leads (white and red) show a voltage of 0v? After all, there is no voltage difference between the two leads.

white is the color for neutral conductors....and reading 2 120v that are opposite phases SHOULD read 240v....

Its supposed to make 240V, its a 120/240 generator. It has two single pole 20 amp breakers on the generator itself, with outlets 120V outlets throughout the truck. Then back in the rear of the truck is a wired in 240V outlet box, with its own dual pole 20 Amp breaker on it. There must be something wrong with the windings or phasing I guess, that's a little beyond what I know about generators. I have so far only used it for 120V. I know quite a bit about adjusting this generator for Htz to make it run properly, the same generator runs the hydraulics for the boom via pump on the end of it, that is 95% percent of the time why I use it. That's a reason its hard to get to much on it to check windings etc, this pump blocks access to the cover for the windings wiring, voltage regulator, etc.

This was a former phone company truck, im sure the 240V outlet worked at one time, but even at the generator across the two 120s I do not get 240V. I had heard that it may need a load to actually make 240V, I didn't know if it was true or not though.

Have u checked the breaker/reset for the outlet? What type of plug is it? Are u sure u have the meter leads in the right prongs?

 

[amanda11270]

Yes I defnitely have the prongs in the correct place, its wired properly. Its a comparable like 14 30 R type twist plug, I'm real familiar with it.

 

[eljefino]

It sounds like at some point someone needed a "large" eg 30 amp 120V feed for "something" and rewired inside the generator head or on its way to the twist-lock.

IOW just taking "half" of the available 240, all one leg, was popping breakers or making the generator unbalanced.

 

[Rookie2]

check at the genset.

 

[amanda11270]

I have had the two breakers right at the generator panel cover off and right there I even only get 120 x 2, no 240, I know a lot about the wiring end of this, just not the internal generator end of what would cause this

 

[eljefino]

Say you have a 3300 watt generator.

This would be good for 220 V at 15 amps or 110 V at 30 amps. But with what is effectively a pair of 15 amp windings. Now you have one monster "thing" that needs 25 amps at 110. It only uses half the windings and pops breakers.

But, if you re-wire the generator so both sides of the windings are in parallel and not out of phase with each other, what one wants is now available. You see this sometimes on older generators that have a "110/220" switch on them and have a faceplate with some 110 and some 220 outlets. Flipping the switch to 110 kills the 220 outlet and only benefits the 110 under the specific circumstance of one heavy load.

While you're at it, see if you have that switch, or can dig it up on the schematic.

 

[amanda11270]

Okay, I did some more investigating into the generator, I think whoever said that it may have been rewired for a higher output, maybe correct. It has had some kinda work done to the winding part of the generator. There are some non-factory crimp connectors coming out of the part that looks like a big electric motor case, or the actual generator assy. Im not certain if I want to attempt to change it back. I have the manual on it, but I dont want to mess it up as Im not certain how many parts are available for this generator yet, cause I dont believe Kohler makes generators anymore.

 

[theoldwizard1]

First, I doubt that it was rewired for higher output.

Second, how did you measure the voltage on the connector labeled "220 Volts" ?

It appears that is a L14-30R. You should get 220V across "X" and "y" (see picture).

 

[Rookie2]

i may have a manual somewhere. i'll get back to you. It is basically a 4 wire generator (two 2500watt 120volt generators) that can be wired for 120/240 or 5000watt 120volt. If someone messed with the wiring they may have inverted one of the 120v outputs (switched both wires)

 

[amanda11270]

Im positive im reading the 240 receptacle correctly, I used numerous 240V receptacles over the years, and am familiar with their wiring enuf to know that people wire them incorrectly, so of course I tried every possible configuration to try and find my 240V. Im a pretty good troubleshooter.

Its definitely an internal generator issue, I just am not familiar with the generation of electricity enuf to know what to look for, its probably a switching around of some wiring to make it run back into the 120/240V. I can tell you all of the 120 outlets work on the truck and there are 4 total.

I also know what it means when it is single or triple phase as I have wired many motors and equipment that is single or triple phase. But when you start saying im not getting 240V because it is not on the same phase you lost me, I guess it means they are both like L1? And I need an L1 and L2?

 

[Rookie2]

what didn't you understand about what i just wrote at 7:38 ?

Found my manual : Kohler TP5394

at the generator 4 leads marked 1,2,3,4

#2 & #3 are tied together = LO or neutral

#1 & #4 are the 240v output (#1 to LO =120v and #4 to LO =120v)

ALSO: in your Generator picture there is one circuit breaker OFF !

 

[theoldwizard1]

...when I go to put my meter leads into the 120/240V outlet, I get the two individual 120 sides, but together they do not make 240V.

Time to go behind the panel !

From one hot (black) to ground (white), you should get 110V. From the other hot (red) to ground (white) you should get 110V. Black to red, 220V.

See if you can trace the black wires to a 110V outlet and the red wires to a different 110v outlet. Put a 110V load on both and recheck black to red for 220V.

If it still reads zero, they are shorted together somewhere further upstream.

 

[amanda11270]

I have already done exactly what old wizard had said before I even posted this topic about my generator. Its got to be before the breakers (which im aware in the photo one was turned off as I've tried every configuration of breakers to see if 240 appears). They must both (hot wires) be running from the same 120 source in the generator itself, I will have to investigate it this weekend. Some of the wires are labelled like factory type tags, and some have colored tiny zip ties on them like someone may have taken them off to remember what was what, but im not certain what that wiring does yet. But it looks like it comes out of the actual winding portion of the machine.

 

[eljefino]

What about your 110 outlet, trace the wires. If it can do 220 the 110s hots should be isolated. If it's been rewired for "super 110" there should be something in common. Though they probably did "the mod" between the fuse/breakers and the gen head.

edit, what wizard said.

 

[wyliesdiesels]

Im positive im reading the 240 receptacle correctly, I used numerous 240V receptacles over the years, and am familiar with their wiring enuf to know that people wire them incorrectly, so of course I tried every possible configuration to try and find my 240V. Im a pretty good troubleshooter.

Its definitely an internal generator issue, I just am not familiar with the generation of electricity enuf to know what to look for, its probably a switching around of some wiring to make it run back into the 120/240V. I can tell you all of the 120 outlets work on the truck and there are 4 total.

I also know what it means when it is single or triple phase as I have wired many motors and equipment that is single or triple phase. But when you start saying im not getting 240V because it IS on the same phase you lost me, I guess it means they are both like L1? And I need an L1 and L2?

Yes, thats exactly what that means. In a split phase, 120v/240v 3 wire circuit, L1 and L2 are out of phase of each other.