Stepper motor power supply from micriwave oven?

[jhovel]

I've discovered that a microwave oven transformer can have it's high voltage frame connection (why do they ground the high voltage to the transformer frame?) insulated quite easily.
When I then feed 240V mains into that coil, the original primary gives me 26V on the transformer I tested.
The wire used on this transformer looks like it would easily cope with 10 Amps or more.
Would this be a suitable and safe starting point for a ~32-36V powersupply for stepper motors?
These transformers are easy to get - they seem to survive the demise of the microwave tube thingy...
Cheers,
Joe

[Al_The_Man]

There have been a few previous posts here on this in the past, I believe Bubba did one such explanation.
if you search the forum with 'microwave' you should find some.
This is one Microwave transformer built power supply
Also, some micro wave transformers had a magnetic shunt in them for regulation, it is worth looking to see if this can be punched out.
http://www.users.on.net/~endsodds/psrewind.htm
Al.

[jhovel]

Thank you for the links.
I had actually read Bubba's article.
My question isn;t related to rewinding the transformer - I want to know what the issues are using the high voltage secondary as a 240V PRIMARY and taking whatever was coming out of the original primary as my supply voltage.
Cheers,
Joe

[Al_The_Man]

From my calculations the problem is the turns/volt are going to go way up which decreases the ratio of the inductive reactance to the resistance of the winding, which means you may not be able to run it at the same VA level as the original.
You can always try it in the application you have and see if there are any down sides that show up.
Al.