Transformer winding

[Bushbaby]

Hi All,
Can anyone of help/guidance here please.

I have always considered buying a coil winder and I have an opportunity to buy an Avo Douglas Model 3 coil winder.

Does anyone have experience of using one? Where can I obtain components such as laminates; bobbins and copper wire (Brocotts seems good?). Once wound, how do I test a transformer to ensure that its safe to use?

Many thanks

Rob

[Mark R]

Ed Dinning is the man to answer that Rob.

cheers Mark

[Ed_Dinning]

Hi Rob, a good machine, but make sure you have all the accessories.
Winding supplies ~ see if there is a local winder who will sell you lams, bobbins and wire as well as polyester tape.
Testing is usually done with a variac and voltmeter plus ammeter.
First test is to look at the no-load current at nominal voltage on primary (if too high then you have the wrong core or have stached it badly). Then look at the ratios of the windings off load and with nominal pri voltage. These will normally be above the required level but will drop on load. If really into designs then you need a load bank so you can look at the regulation of the tranny.

The other things worth getting are manufacturers catalogues (or downloads) for the various sizes and types of lamination. Very old catalogues are useful as most lams are now metric, and it is usefull to be able to compare them to old imperial types when doing re-winds.
An HV "flash tester" is also a good accessoriey so you can apply 2Kv for 1 min from pri to core and secs.

Ed

[AlanBeckett]

Rob,
If you got your Lathe going you wouldn't need a Winder
Alan

[Bushbaby]

Hi Ed,
I've an older (not Evershed and Vignoles) megger (if i recall its ex GPO) in a leather case from I think its 1960s. Will this be ok to perform the HV flash testing??

Thanks

Rob

[Ed_Dinning]

Hi Rob, that should do if it goes up to at least 1KV; you should expect at least 10M on a good new transformer.

Ed