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Thread: convert 3 phase to single phase
04-02-2012, 01:06 PM #1
convert 3 phase to single phase
Wondering if anyone can help me
I know a bit but not alot about electric motors, and also a little less about Phase converters, inverters, only that it enables you to run 3 phase electric motors on a domestic 240v household supply, but as very recently I found out that this is not the full story, and it can get quite expensive. I bought a Emco maximat 10v Milling machine that was fitted with a 3 Phase motor, I thought this will be ok , I will just go out and get a phase converter/inverter priced it at £75 all in (I live in the UK), spoke to the person on the phone ,they asked me just to make sure, is it a Dual Voltage motor they said, I went and looked at the motors spec plate, it only read 415v , the person on the phone took a sharp intake of breath and said it's not dual voltage then, and said to me that you will need this and that at a cost of 200 and something ££s.
I need advice,
Is there any other way to make this electric motor run without me spending over £200, it's only a small motor. I would most appreciate anybodies help/advice
Last edited by leeh; 04-02-2012 at 03:34 PM. Reason: convert single phase to 3 phase
04-02-2012, 05:09 PM #2
Did he mention adding a transformer?
04-03-2012, 01:03 AM #3
I am not sure if he did mention a transformer, he just rattled off what I would need, but at this time hearing the price he was coming out with, I just dismissed the all idea, with the jump from £75 up to over £200 because it wasnt dual voltage.
Transformer? do you have an idea how I can make it work
04-03-2012, 04:00 AM #4
Here in Australia when a 3 phase motor approx. 5 hp or less and rated for 415 volts it is Star Connected internally. What this means is the motor has 3 windings which are 240 volts each. Now what has to be done is remove the bell ends of the motor and have a very thorough inspection of the area of the windings where the 3 wires enter the windings, what you are looking for is called the Star Point, this is the connection of the other ends of the 3 windings, it will have a seperate piece of insulating sleive around it.
When you find this star point carefully lift it away and remove it's insulation and disconnect these 3 wires. Now individually attach 3 new Insulated wires. Insulate your connections and secure these wire so as not to vibrate and bring the 3 new wires into the terminal box. With a meter you will easily identify which new wire electrically connects with which original wire, now you have 6 wires in the terminal box which have to be connected in Delta for the motor to be 240 volts 3 phase.
If you need any further on Delta Connection just let me know. Be very careful digging around your stator windings, it might be an old motor and could have very brittle insulation and don't forget to Re-Mark the motor's new statis 240V Delta Connected and let me know how you get on.
04-03-2012, 06:42 AM #5
Thanks Jim for your reply,
This is what I have so far, My lead wire has Yellow/Green, Blue , Brown , Black, all joined up to little thin Red wires running into the windings, that is apart from the Yellow/Green wire, it's joined up to a thicker wire running into the windings but I cant work out the color of that one.
04-03-2012, 09:46 AM #6
Before digging around in the motor, what does the nameplate say? Is it single phase or 3 phase. If it is single phase as i gather from your opening post, then a simple single phase transformer will do. Perhaps a photo of the nameplate?
04-03-2012, 10:36 AM #7
I would try to buy a used motor, & make an adapter if possible.