This is not Arduino related so apologies in advance if this is too off topic but I know there are very knowledgeable people on here so I thought it worth asking.
I have a 4.5Kw (Chinese made) single phase 240 volt generator which has some windings of the stator coils flashed over and burnt.
It is certainly not worth a repair shop doing the rewind so I would like to try this myself to further my knowledge and hobby. The time needed to do it is no concern, I will feel very rewarded if I can do it.
It is a 10 slot stator using 0.8mm wire with a separate coil of 0.6 wire for the AVR sensing.
As it is very difficult to dismantle the coils to see how they are wound I am hoping that someone may know.
I can count the number of turns and see that it uses four wires teed together but would like to be sure of the correct configuration of the connections for output and AVR comparison before I begin. Obviously I have the correct size new wire and insulation etc.
JohnLynn:
As it is very difficult to dismantle the coils to see how they are wound I am hoping that someone may know.
The first step you need to do if you are to repair this is to dismantle the coils and unwind or remove them.
For a comercial product unless the service manual is available and has details of the winding, your only
recourses are to contact the manufacturer and ask, or reverse-engineer directly (or check on Google
if someone's already done this!)
Flashover suggests the winding is indequately insulated in the first place - so you'll have to consider adding more insulating layers if there's room on the former.
Since you can see the damage, you should be able to repair the damage. Carefully! But as mentioned, the problem is probably poor manufacturing.
The rotor or stator of any motor or generator must be properly insulated and wires locked in place. This is done by placing the piece in a vat of insulating varnish and placing both in a vacuum chamber to draw all air bubbles out if the windings. Then the piece is placed in a oven to cure and harden the varnish.
Seems the Chinese failed to do the final manufacturing step.
Thanks to all of you for your help, it is much appreciated especially as it isn't Arduino related.
I have repaired another stator on a very similar machine, luckily for me it was fairly obvious which wires had burnt and I was able to "piece" them out.
This one however has several wires melted where they actually leave the slots so impossible to repair. Although I have dismantled the AVR coil the main windings are stuck together and stuck in the slots with varnish so I can't see how to unwind individual wires from the stator slots. I think that a professional rewind company would burn the old windings in an oven, does anyone know what temperature is needed to do this and if this results in the varnish/glue becoming soft or disappearing completely?