Can somebody confirm this is the motor windings star point

[M K]

people mentioned to me before about pulling the star point from my 3 phase 415v motor to make it 240v 3 phase but I declined due to not wanting to mess the motor up but after seeing a video of what I should be looking for I think I have found it easier than I first thought

Can somebody confirm that these 3 soldered twisted wires are what I have to seperate, add on new wires to and bring out to the terminal block to make the motor 240v 3 phase?

Also how can I tell which is which? I can't buzz them as all wires in winding are touching

Thanks
Marc

 

[AdrianH]

It would certainly look like it.

If you are happy to unsolder them and believe you can solder wires to them to go to the outside, then go for it, once separated you will be able to find which one mates with the terminals easily.

Adrian

 

[M K]

Thanks

I had a quick google search also and I was able to buzz out the wires to find what's what but only directly on the clean cut end as the wires are coated so don't show any continuity unless the probe is touching the cross section

Identified what's what so will solder them in the week and heat shrink them

Which wires go to which though? Or do they go in 3 matching pairs?

My terminal box on the motor only has the 3 studs so is there any reason I can't just put both crimped ends of each pair over each stud? Can't see why not

Many thanks for the help with my never ending questions

Marc

 

[AdrianH]

To make them 240 Volts 3 phase, you really only need the three studs and bring the extra wires through, crimp or solder ring terminals.

So if you have W and the other end of the wire call it W2, U and U2 and V and V2.

Then you now want to make a ring out of the three windings.

Start with the new end W2 and place over U, the new end U2 place over V and the new end V2 place over W. That is your ring or delta configuration.

Connect your three wires to W, U and V, if the motor goes in the wrong direction reverse two wires from the inverter, simples.

Adrian

 

[M K]

That's perfect thanks

So new end of each wires joins to the adjacent wire

Thanks
Marc

 

[AdrianH]

Like that.

Adrian

Yep

 

[Pete.]

The star point is nearly always easy to get at so the motor winder can flash each winding individually before joining them up.

Basically you can't get wiring it in delta wrong unless you happen to manage to get both ends of the same coil connected together. Cut the star point right off close to the joint so you have three loose ends. Free up enough wire so you can solder fly leads to it - you'll need an inch at the very least better to have two. You might have to cut back some lacing but if you can wiggle the wires out from under the lacing then that's better. Use a stanley blade to carefully scrape all the enamel off the copper wire back about an inch. Get your 3 new motor leads and tin about 3/4 of an inch of the wire at the end. Wrap the copper wire you have scraped clean around the tinned lead 3 or 4 turns then solder it so that the copper wire comes off the end of the fly lead straight, to prevent a kink which might break. Slip some heat-shrink along the wire over the joint and use that to insulate it. If you have a significant amount of copper wire free then slide the heat shrink up that too (see below).

It's most important that you secure any loose copper wire by tying it tight the windings or even put some thin shrink sleeve over it and tie it back somehow. All that lacing and varnish you see has a purpose and that is to prevent the copper wires rubbing against each other and causing a short. When the motor is running, those copper wires WILL try to move a tiny bit and wear through the coating then before you know it the motor lets the smoke out, so just take that simple precaution and you'll be fine.

There's absolutely no reason why you can't put the six wires onto three posts, you could either crimp two wires to a ring terminal or stack the terminal rings on the post. Just make sure that you don't have two ends of the same coil on any post.

 

[M K]

Ok got it

Thanks for all the info

 

[M K]

Got the new wires on but have currently left it wired in star configuration so I can take it into work tomorrow and test it still works normally in the fitters workshop that has normal 3 phase sockets as I do not have an inverter to test it on yet in 240v 3 phase delta

I heat shrunk the new wires in some raychem dr-25 heatshrink I had after soldering the 3 new wires on and doing a continuity test

Hope it works as I never actually see this motor run but bought it in good faith

 

[Wedg1e]

Good effort, fingers crossed
It's one of those things that on first glance seem really complicated but actually aren't.

 

[M K]

Well tonight I found a 3 phase socket in our yard and plugged the motor in direct and .......NOTHING !

I can't be sure that socket was good though so will have to check on another one when I get a chance but if the motor is dead then I don't think I did anything wrong and I can't return it to the seller as I've messed with it now so I should of checked it worked before I messed with the windings as il never know if it was me or it was duff already?

The windings can't be broken as I can buzz test 1 end to the other on each u1/u2 v1/v2 w1/w2

I have earth on the fat pin and the other three phases don't matter which order they are in do they?

Thanks
Marc

 

[Pete.]

If you have a 4-pin plug with earth on the fat pin then you can't get it wrong, the motor will turn one way or the other. If you have a 5 pin plug then one of the small pins is neutral which you won't use. If you use 2 live pins and neutral the motor will hum but not turn.

Probably the socket is not live.

 

[M K]

Yeah it's 3ph and earth plug NO neutral so hoping socket was dudd if not that's £100 down the pan!

 

[Pete.]

Can't be anything wrong with that motor. The windings look good (as in not cooked) and if you have continuity between all phases then what can be wrong?

 

[the snooper]

Yeah it's 3ph and earth plug NO neutral so hoping socket was dudd if not that's £100 down the pan!

was it 3 ph 240 ? if 415 and if it had have worked it may have damaged the motor

 

[Pete.]

Nothing wrong with those windings mate look at the colour of them. If it was cooked it'd be full of black stinking mess. It'll be the power supply is dead I'll stake my left jamb-nut on it.

 

[M K]

It was only 415v before I pulled it apart

As said I have continuity between each end of each wire before and after soldering and sleeving but I never see it run before I bought it off eBay just the sellers word for it?

I will find a 4 pin socket that I know works and I will test it again or il order my inverter this week as I will be needing that regardless and then test it in 240v delta via the inverter

Thanks

 

[the snooper]

It was only 415v before I pulled it apart

As said I have continuity between each end of each wire before and after soldering and sleeving but I never see it run before I bought it off eBay just the sellers word for it?

I will find a 4 pin socket that I know works and I will test it again or il order my inverter this week as I will be needing that regardless and then test it in 240v delta via the inverter

Thanks

Did you check for continuity between the three connections after soldering

 

[M K]

Did you check for continuity between the three connections after soldering

Yes mate and all was ok

 

[penfold]

If the windings are intact and you have power but it still isn't spinning it isn't wired up right; the diagram up the page shows how they need to be connected for delta. Putting 440 through it momentarily for a test won't do any harm, just don't leave it running.