how do you convert a three phase generator to a single phase 240volts generator with diagrams?

Question

240 volt generator with diagrams

Answer 1

I will assume the generator you are referring to supplies three phase 120V/208VAC. If it has a twelve wire alternator it can be rewired to supply single phase 120V/240VAC. Some generators have a selector to change between the two outputs. While operating on single phase, the maximum output power available is 2/3 of the maximum at three phase.

While operating in three phase mode, each pair of windings is operated in parallel. Each phase to neutral is 120V for each output, and 208V between either two line outputs. If each output winding is capable of supplying 1kW, total available output will be 6kW.

While operating single phase, output voltage between neutral and either line will be 120V, and 240V between the two line outputs. One set of windings is reconfigured to operate in series rather than parallel. This is the start of the 120/240V configuration. Each of the 'angled' phases is put in series with the other phase which is 120 degrees out. When the two are added in series it results in an output voltage of 120V at the same phase as the original two lines. Due to the phase angle, the output power available from each of these windings is only 1/2 of what is available in three phase mode. Thus total power available while operating in single phase mode is 2/3 of the three phase maximum.

Check the quick hand drawing of how this works. Each of the six output coils are A-B C-D E-F G-H I-J K-L. The upper diagram shows how they are configured for three phase operation. The lower diagram is single phase.

http://members.rennlist.org/warren/3-phase.jpg

Clearly the diagram is not intended to show how to rewire a generator, but rather to show how the system works.

Answer 2

You say Japanese generator, was it made for export? you'll want to be sure it is 60Hz, your air conditioners probably won't like 50Hz. Your single phase appliances will run on one of the three phases. However, to utilize the full generator output you'll have to distribute the loads over all three phases, you can't get the full capacity out of just one. If you are using a transfer switch to use your existing breaker panel and house wiring you will have some problems getting full capacity since your existing panel is probably not three phase.

Answer 3

thinking outside the box, why bother rewireing
Just use the 3 separate phases and use each to power the appliences you want, keep the loadings balanced between the phases as much as possible. Say you want to light 3 lamps, stick one each on each phase. You don't have to balance the laods exactly, but the closer they are to equal the closer you can get the the max loading for the genset without causing damage. Follow the advice in some of the other answers regarding getting the right voltage, either between lines or lines to neutral, depending on the output of your set. Also head their advice re safety! When the load is unbalanced, the voltage of the neutral will move away from zero. Monitoring its voltage, gives you a clue as to how out of balance your loads are and allows you to adjust.

Answer 4

A 415v 3 phase generator has three live cables plus one neutral or earth. The voltage between any one of the live cables and the neutral is 240v and can in theory power a 240v single phase appliance. The voltage between any two of the live cables is 415v.
Unless you are very careful and have a good knowledge of electrical engineering practise I would recommend that you don't take a chance and get a single phase generator,

Answer 5

Just use 2 of the leads (assuming it's a 240 volt generator). It makes no difference if it's delta or Y wound (unless the Y is center grounded through the generator) but you will only get about 1/3 as much power out of it as what its ratings say.


Doug

Answer 6

Rough and ready way - just take off from 2 of the lines, but this is liable to cause unbalance if you are approaching max power take off.
Ideally use a 3 phase to single phase transformer.
Otherwise you will have to dismantle the generator and resolder the winding - if possible. What type of machine is it? Afraid this would be far from a trivial exercise.

Answer 7

yeah go with the big bonfire!! Can't draw diagrams in yahoo answers so cant explain!
sorry!

Answer 8

Transformers---- more than meets the eye

Answer 9

get a proffessional electrician to do it or you will kill yourself or someone else

Answer 10

big bonfire