Railcar generator hookup

tpk · **Posted:** Mon Dec 24, 2007 11:01 pm

Recently, our group purchased a gen-set for use on our crew car. It is one of the venerable Detroil diesel 3-71 with a 25KW generator. My question is, how is it supposed to be wired to the car? It is 3 phase, 240 volt, delta wound. I am familiar with 3 phase systems. However, I've been told three different things about this generator; one, it was only used to drive a "genamotor" set that was under the car. Two, one of the phases has a "wild leg" for 120 volts. Three, the frame of the generator is the neutral side, which needs to be "bonded to the car body/frame/breaker panel. I am wiring the car with a 120/240 volt 3 phase breaker panel, with a neutral buss in the panel. From what I've heard, I may have to buy an isolation transformer to make it work? The set is a model E-991, serial number 29-K-54. I have been unable to find any info on this generator on the "net".

BML1149 · **Posted:** Tue Dec 25, 2007 12:56 pm

TPK,
If your generator is a "delta" 3 phase, it does indeed have a "wild leg". You must be very careful when splitting the legs to get 120 volts that you have the correct 2 legs. If you don't, it will fry anything that is 120 volt plugged into it. I would strongly encourage you to find a local electrician who is familiar with commercial 3 phase generators to help you. I don't know about the "genamotor set" you mentioned , but , again, a good electrician who knows commercial 3 phase should be able to help you. Also, if you plan to have a "shore power" connection, it must be correctly wired in and have a proper transfer switch in the car so that it may be safely transfered from "shore power" to "generator power". Good luck with your project.
Leverett Fernald

fkrock · **Posted:** Tue Dec 25, 2007 2:19 pm

Most gensets I have seen were assembled by a company that buys an engine and then mates it with a stock alternator from another source.

If you can find what company made the alternator, you may be able to get wiring information. Typically you will have six or twelve wires coming from the alternator that go to a terminal box on the genset. How these wires are connected to each other determine external electrical wiring. This allows the genset to be connected to the largest possible number of external wiring plans.

fk