OT generator

A little off topic, but farm related if anyone has an answer. I have a 90amp 3 phase generator for sale and the guy who is interested in it asked me if it will run a 30 and 50 horse motor at the same time. Everything is 3 phase, I believe 240 volts.
Any help appreciated.

Assuming your generator does put out 240 V, then Power = V X Current or 21.6 Kw. 1 HP~.75KW. So you generator produces 28.8 HP. However there will be some losses as well. You probably couldnt run even the smaller motor alone with the generator.

240/416 ? The only real three phase with 240 and
which is in Europe and isolated locations in Canada.
Or is it 120/208 ?

I'll have to look, it must be 120/208 I guess.

This link calls for 128 full load amps for 50 hp motor Boy that are not cheap


http://www.amazon.com/Dayton-2MXX5-Motor-50hp-208-230/dp/B001QROXHC

I worked for many years in a plant with 240 volt three phase systems. In one building we had an old 240 volt delta system, with no mid-point tap for 120 volt. We used step down single phase transformers to create 120 volts. Essentially they were 1:1 transformers, with a center tap on the secondary for 120 volts, single phase. The other building had a "Red-leg delta" system, which was a 240 volt, 4 wire, three phase delta system where the center point of one phase was tapped to provide 240/120 volt single phase power. These are not uncommon systems in industry where 120 volt loads are low compared to three phase loads. The 208/120 three phase wye systems are usually used in applications where 120 volt loads are relatively higher, although we used that system in on are with a high concentration of Japanese machines which were 200 volt three phase. The 208/120 system kept the three phase voltage within 10% of nominal for those machines and avoided step down transformers. It was also within 10% of our American 240 volt three phase machine, so it worked well for us. Just a thought.

(quoted from post at 16:27:31 11/04/11) Assuming your generator does put out 240 V, then Power = V X Current or 21.6 Kw. 1 HP~.75KW. So you generator produces 28.8 HP. However there will be some losses as well. You probably couldnt run even the smaller motor alone with the generator.

Click to expand...

Might want to re-visit that 3 phase power calculation!

P=3 X E (line-to-neutral) X I

or

P=square root of 3 X E (line-line) X I

both yield same answer, which is 1.73 times your 21.6 KW or 37KW, which by your KW to HP conversion would be 50HP.

We have that Red-leg delta system here powering irrigation pumps. 240 between any two legs. 120 from the first two legs to ground, and then the 3rd leg (or Red leg) to ground measures around 215. I know you don't want to use that high leg to power the lights and outlets in your pump houses.
David

I pulled out my handy sliding calculator:

240 VAC 3 PH

50 HP = 150 Amps FLA
30 HP = 80 Amps FLA

I would not be comfortable running either motor on that
generator.

B&D, ever hear of 240 Delta?

Red leg delta, AKA: Y - one leg out / open delta! High leg often referred to as the ba$tard leg!
Edit: 2 phases of Y primary provides 3 phase delta secondary.

Delta secondaries are never ever used around
here.
120/208 four wire, some rare 240/416 four wire,
three wire 600V on very large services and 347/600
four wire.
Only time we use 277/480 is on specific
equipment not manufactured in 208V or 600V. There
are some 600 to 277/480 delta-wye transformers
around.
Dual voltage 220/440 motors are uncommon but
connected to 208V or 416V. They seem to operate
ok.
Have never ever seen a 208 transformer with a
delta secondary. Always a wye to provide a
neutral.
347/600V lighting panels are supplied from a
transformer with wye connections. Usually the
347/600 neutral comes from the utility
transformer's wye point.
Or on occasion a 600V to 347/600 delta/wye
transformer is mounted near the lighting panel. If
the building is supplied with only 600V three wire
from a very large service.

(quoted from post at 12:39:17 11/05/11) Delta secondaries are never ever used around
here.
120/208 four wire, some rare 240/416 four wire,
three wire 600V on very large services and 347/600
four wire.
Only time we use 277/480 is on specific
equipment not manufactured in 208V or 600V. There
are some 600 to 277/480 delta-wye transformers
around.
Dual voltage 220/440 motors are uncommon but
connected to 208V or 416V. They seem to operate
ok.
Have never ever seen a 208 transformer with a
delta secondary. Always a wye to provide a
neutral.
347/600V lighting panels are supplied from a
transformer with wye connections. Usually the
347/600 neutral comes from the utility
transformer's wye point.
Or on occasion a 600V to 347/600 delta/wye
transformer is mounted near the lighting panel. If
the building is supplied with only 600V three wire
from a very large service.

Click to expand...

"Delta secondaries are never ever used around
here. " "Here", being north of the good old USA, right? Well, you can find plenty of delta xformers with tap at center of one winding for neutral, down south.