using just 2 legs of a 3 phase gen

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tschukojr

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a friend wants me to install a generator transfer panel at his home, ( probably a, reliance --TRC0605C---)---but he wants to use his big welding generator, to supply it, and its a 3 phase,50 amp,--i have'nt actually tested it yet-----i assume its 110/ 220-----, i'am concerned it could damge the generator, using just 2 legs, i know people have done it---but if run for an extended period could the unbalance cause damage or overheating-- also if its 208-- hows that gonna fly for use in a residence--any input would be appreciated---------tony
 
If you are using only two phases of the three available on the generator, then it is obvious that you are using only 2/3s of the power available from the engine. If this is a six cylinder engine, this is easy. You just have to determine which of the four cylinders are powering the active phases and disconnect the other two [turn off the fuel and spark plugs].
With eight cylinders this is more complicated. You can safely shut off two of the cylinders but will have to abide with a little bit of asymetrical thrust.
As for the 208 volt issue, you will have to use an auto-transformer to bring things back to a normal 220 volts. Otherwise you will suffer the usual pangs and misfortunes of an underpowered whatever.
~Peter
 
peter said:
If you are using only two phases of the three available on the generator, then it is obvious that you are using only 2/3s of the power available from the engine. If this is a six cylinder engine, this is easy. You just have to determine which of the four cylinders are powering the active phases and disconnect the other two [turn off the fuel and spark plugs].
With eight cylinders this is more complicated. You can safely shut off two of the cylinders but will have to abide with a little bit of asymetrical thrust.
As for the 208 volt issue, you will have to use an auto-transformer to bring things back to a normal 220 volts. Otherwise you will suffer the usual pangs and misfortunes of an underpowered whatever.
~Peter
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H'mmmm

Your kidding right:roll:
 
wow---thanks for thoose answers, ( you guy,s are at the top of your game) --but i guess being close to retirement and having gone to apprentice school over 30 yrs ago-- ive lost my edge------------------why bother playing with the motor at all, this is a very large industrial welding generator - its on a trailer, i really wouldn't touch anything, internal----just wondering about an un-balance causing heating or something else---i know lots of people have done it , but over time is it a good idea,------also like i said its been 30 yrs but do i rember right about the voltage----if its within 10 % either way is gonna not suffer from under or over voltage--( rule,s of thumb )----thanks again ---tony
 
tschukojr said:
wow---thanks for thoose answers, ( you guy,s are at the top of your game) --but i guess being close to retirement and having gone to apprentice school over 30 yrs ago-- ive lost my edge------------------why bother playing with the motor at all, this is a very large industrial welding generator - its on a trailer, i really wouldn't touch anything, internal----just wondering about an un-balance causing heating or something else---i know lots of people have done it , but over time is it a good idea,------also like i said its been 30 yrs but do i rember right about the voltage----if its within 10 % either way is gonna not suffer from under or over voltage--( rule,s of thumb )----thanks again ---tony
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Yes, the problem is the unbalance.

Since you have only two phases working, that will lead to an unbalance output of the generator. It will cause Heating because of the harmonics of negative secuence kind. This kind of harmonics cause that the rotor of the generator tend to run the opposite way that it was meant to, this causes vibrations unwanted in the machine, and increase of the heat as well.

Meassure the harmonics if you can, and see the values of the 5th, 11th and 17th. See (Fitzgerald, A. E., Kingsley Jr., C., and Kusko, A., Electric Machinery, McGraw-Hill, New York, 1971.)

From the voltage point of view, I think 10 % will be fine, due to the conditions that you will put into the machine.

Anyway, the machine will suffer because it was not design to operate that way.
 
tschukojr said:
a friend wants me to install a generator transfer panel at his home, ( probably a, reliance --TRC0605C---)---but he wants to use his big welding generator, to supply it, and its a 3 phase,50 amp,--i have'nt actually tested it yet-----i assume its 110/ 220-----, i'am concerned it could damge the generator, using just 2 legs, i know people have done it---but if run for an extended period could the unbalance cause damage or overheating-- also if its 208-- hows that gonna fly for use in a residence--any input would be appreciated---------tony
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Why dont you use the three legs?

110? 220? or 208?

if it is 208, you would have a 120 V. And its gonna "fly"
 
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