Thought I would share this brilliant genertor tip

[Industrial Toys]

A friend of mine who is an electical genius first introduced this idea to me. Not sure what code has to say about this.

It allows you to run a generator and always have it nicely balance for load.

You put an appropriately sized transformer on the genset output and run 240 into from the generator without a neutral. Then your load connects to the same place, but with the centre tap for the neutral. See, you don't even need to use the other side of the transformer, as long as the side you are using has a 120/240 tap. You are in essence making your own Neutral! You could, if you had one, use the other side of the transformer if it had 120/240 windings but I imagine it might be hard to find a transformer like this as it has little application. I have such a transformer permanently wired in on the generator side of my transfer switch.

Now, thinking about keeping the load balanced is a thing of the past. On a smaller genset, you can really hear a knocking when you put a heavy 120 volt load on one side. This also allows you to use all of your genset capacity, especially usefull if it is on the small side.

 

[Xfaxman]

A friend of mine who is an electical genius first introduced this idea to me. Not sure what code has to say about this.

It allows you to run a generator and always have it nicely balance for load.

You put an appropriately sized transformer on the genset output and run 240 into from the generator without a neutral. Then your load connects to the same place, but with the centre tap for the neutral. See, you don't even need to use the other side of the transformer, as long as the side you are using has a 120/240 tap. You are in essence making your own Neutral! You could, if you had one, use the other side of the transformer if it had 120/240 windings but I imagine it might be hard to find a transformer like this as it has little application. I have such a transformer permanently wired in on the generator side of my transfer switch.

Now, thinking about keeping the load balanced is a thing of the past. On a smaller genset, you can really hear a knocking when you put a heavy 120 volt load on one side. This also allows you to use all of your genset capacity, especially usefull if it is on the small side.

How do I determine the appropriate size?

 

[SPYDERLK]

Its called an autotransformer:

McMaster-Carr

 

[buickanddeere]

Been doing that for years after discovering the concept of load balancing was beyond the wife and children. Otherwise a 15KW+ generator is required for a 10KW household load.

 

[Industrial Toys]

Yes,an auto transformer. Even though I don't for the life of me know why it's called that.

I'm just guessing that the KVA rating should be that of the KW rating of the generator, or larger.
But I'm not sure. I aint the Rocket Scientist.

 

[npalen]

Autotransformer - Wikipedia, the free encyclopedia
See section entitled "LIMITATIONS".

 

[buickanddeere]

Yes,an auto transformer. Even though I don't for the life of me know why it's called that.

A portion of the windings is common to the LV and HV side. No true magnetic separation.

I'm just guessing that the KVA rating should be that of the KW rating of the generator, or larger.
.

Depends but figure a 10KWA transformer for a 5KW generator. All the power maybe demanded across half of the windings.

 

[Gary Fowler]

How would one wire one of these to his generators power supply lines to get the full wattage load out of the generator when all come with just a 30 amp twist lock connection and then a few 120v power outlets.
What size would be required for an 8000 running/ 10000 surge watt genset assuming that you wanted input to be 220v and output to be 220v so you could power both A and B sides of your breaker panel.

 

[Industrial Toys]

I guess it depends on how your generator is used. I assume that most people have some method of connecting it to the wiring of their home, but I guess I'm wrong.

So let me say, that I have another "portable generator" that I also intended to do this. I have the transformer and had a plate bent to mount the transformer to the tubular frame of the generator, but didn't do it yet, because the genset is already heavy as heck (being a Yanmar Diesel) and this would make it insanely heavy.

Anyway, I would have three wires going to the 110/220 twist lock using the two hot legs and ground, but not neutral. These two would go into each side of the 110/220 windings on the transformer, and ground the frame.

Now, you have to provide your own additional 110 recepticals, with the neutrals coming off the centre tap of that winding you have connected to the generator and the hot leads of recepticals go to each of the hot legs from the generator. It would be easier to draw this, but I have no idea how to put this on the computer.