Is the Star point located to the left the termination box? I see some Grey wires……

That blob at 6 o'clock, could it be that? My theory says that it should be close to the first set of coils (not where the lead out wire are). this is based on the first wire goes around coil #1, then coil #4. . . the second wire goes to coil #2, then coil #5. . . wire number three goes to coil #3, then coil #6. So the ends of the wire must at the last coil, the last but one and the last but two. This should be close to coil #1, or where we came in.

Try picking out one lead out with a sharpi type marker, perhaps you can identify the start or ends of the sets of coils. A colour code would help, black, red and green or blue could be used for the input wires, then any sleeved long wire must go to aq coil or the star point.

If you consider the service of the motor, hot with vibrations, the leads must be supported really well, I am not confident that stripping away all the lacing then trying to replace it all would add to the reliability of the motor, so minimum modifications must be the way to go. Just remembered of some incidents at work, because of the internal temperature rise, the actual coils change shape and move about, just something else to fret about.

Frank

hi steve, ok its not a problem, and this may sound obvious, but you are looking for the biggest lump in the windings, find where the tails that go to the connector block are solered to the windings, and look at the same place on the other side of the windings, and also at the other end of the motor, you cen cut the string binding and remove the taping, but keep bending of the wires to a minimum. when you find the star point, unsolder the connections, solder on some tails of similar size or larger, and route them into the connector box, then tape up the connections and tie them back to the windings with cotton string, and varnish them up to stop them moving , job done!

phil

Star point connection splitting to convert for delta = 240 volt inverter operation (usually).

I have converted 3 so far (a tiddler that was easy as its star point was really obvious with tails soldered on, a 3/4 hp which was less easy and a 1.5 hp which was a pig!). If you look at the tails they used you might be able to identify it by elimination – if you are lucky they used colour coded tails so you want something that is NOT connected to the termination tails and NOT one of the repeated field winding connections. That is a poor description but I cant think of a better way to explain it. If you are really lucky you might have one sleeve with three different colour wires in it – that would be a result!

Mark

Edited By Mark C on 04/10/2015 23:04:37

PS. Don't forget the big green and yellow wire – I reckon after a spot of DIY electrickery in a motor, that becomes very important indeed…..

Edited By Mark C on 04/10/2015 23:07:05

Crimps done well cold weld and are the most reliable way of joining wires.

Neil

Steve,

You might find your luck is in with the coolant pump – they tend to be dual voltage from my experience. You will need another inverter for the coolant pump or the motors will be very un-matched and both will vary speed together – which might be good for matching flow to rpm but I will bet the pump rate will not be linear with rpm! This might be a good time to investigate capacitor running of a synthetic phase.

The switch gear should be capable of re-wiring but it might take a bit of working out (I am assuming it is a "standard" rotary switch with multiple poles). You will then only need an emergency stop switch (assuming you want to wire one) which will shut the thing down if the rotary switch fails or some other disaster ensues. You will probably want to wire for "two wire" control and should be able to find a diagram that works for your inverter along with the correct programming parameters. All that you need then is a pot for speed control – check the value for your inverter as they are not all the same (some 5K others 10 and I have one that needs 4K7).

Mark

Then after checking continuity heat shrink the connections twice and wrap or tie wrap all the wires back into place

colour code or mark each pair and bring the wires out to the connection box and reconnect as delta

Ian

When I wound motors in our winding shop we used oxy-acetylene to fuse the two wires into a small ball. To lace the windings we used flat cotton tape about 10mm wide and a piece of lewmex wire as a needle to thread it through the windings, systoflex heat resistant glass fibre based sleeving was used to sleeve joints.

Mike

Edited By Michael Poole on 05/10/2015 13:26:00

Steve,

2 wire= binary logic IE. Stop is wired with NC switch feeding start & direction NO switches (often of the momentary variety but not exclusively which is why you can use your existing rotary switch). If stop is NOT pressed then start or reverse will result in a signal at the inverter. As long as inputs are latching then things are fine for basic operation. If you want more control you need more wires – I don't know why it is called "2 wire" but it might be due to the logic of the basic switch arrangement being along the lines of binary? Or it could just be a generic name the electricians I know have come to use…..

You will find that the different makes have different ideas but they will all do the same basic operation, it will just be a case of working out how!

Having a workshop running exclusively on inverters I can strongly advocate the use of load reactors (output filters/chokes) on the motor side and line filters on the mains side – I was amazed how effective they are at killing the electrical noise and high voltages. I concluded that messing with winding conversion warranted giving the motor all the help I could in continuing to work and these help a lot.

Mark

Mark

2 wire control is used if you have latching switches so your start switch is n/o and wired in series with a n/c stop switch only if the switch latches on will the inverter start and carry on running

and i dont think this system is a no volt release system as if your start switch is on and the stop switch is out then the inverter will start on power up

Most inverters allow you to make the inputs latching or not.

if you want to use normal switches (unlatching) you need 3 wire control

Ian