RE: [CAD_CAM_EDM_DRO] UPDATE: Stepper and Servo power supplies: Microwave Oven Transformers for sale

TV transformers are not good for this application. They do not have
enough power except for smaller systems (200 watts or so for the larger
color vacuum tube sets - I used to use these for building tube audio
power amps) and the killer is that every TV transformer I have seen had
the primary and secondary wound together on the same bobbin.

The beauty with the Microwave transformers is that the primary and
secondary are physically separate so it's trivial to remove just the
secondary and to wind one that fits your needs.

Dave

> -----Original Message-----
> From: CAD_CAM_EDM_DRO@yahoogroups.com
> [mailto:CAD_CAM_EDM_DRO@yahoogroups.com] On Behalf Of goat!
> Sent: Monday, February 20, 2006 9:28 AM
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: Re: [CAD_CAM_EDM_DRO] UPDATE: Stepper and Servo
> power supplies: Microwave Oven Transformers for sale
>
>
> To think when we moved out of our commercial property, I left
> scores of microwaves. Just didn't have the gumption left in after
> working to move everything else almost 24/7 for two weeks.
>
> Left scores of older TVs as well, though I still have barrels full
> of transformers from them. I have to admit though that I had
> a mountain
> of stuff that I did manage to get scraped. Still had a mountain to go.
> Sure somebody made a buck on scrap on it, as they
> were lined up to get it.
>
> So what about tv transformers?
>
> Goat
>
> Dave Halliday wrote:
> > I am done dismantling the ovens, took several hundred
> pounds of sheet
> > steel to the local recycler to be remelted into A36. Only
> had a couple
> > bags of stuff that had to be landfilled (plastic, front
> doors, etc...)
> >
> > Not done testing the transformers yet but it looks like I will have
> > about twenty of them for sale.
> >
> > I will be shipping via USPS flat rate carton ($8.30) and
> you can get two
> > smaller transformers into a carton.
> > The transformers will be bolted to a sheet of plywood and then
> > surrounded with hard plastic foam (foundation insulation). They will
> > arrive in good condition.
> >
> > I'm selling the smaller transformers for $20 including the shipping.
> > The second one sells for $12.
> > I rate them conservatively for 400 Watts continuous duty. They weigh
> > around 9 or more pounds each.
> >
> > I have a few larger transformers that I would rate at 600 Watts
> > continuous duty. Only one will fit in a box.
> > These are $25 including shipping. These weigh 13 or more pounds.
> >
> > Considering that it will take you about two hours to wind your own
> > secondary and that a commercially made power transformer of
> this size
> > costs from $90 on up not counting shipping, this is a good deal.
> >
> > I have removed the secondary on a few of them (starting my
> projects) and
> > the best way I have found is to clamp the transformer into
> your vice and
> > then use a smallish (16 oz.) hammer and a 1/2" cold chisel to cut
> > through the copper windings. The quickest and the safest. Make sure
> > that you work _away_ from the primary windings.
> >
> > I'll have some pictures up at the Black Mountain Forge
> website in a day
> > or two.
> >
> > Hint: If you have a metal bandsaw, do NOT use that!!! Don't
> ask me how
> > long it took to clean all the little pieces of copper wire from its
> > guts. :-P
> >
> >
> > Email me off list for more info and PayPal account.
> > Sales to USA only please although I will consider Canada --
> > international shipping is a pain.
> >
> > Dave
>
>
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bill
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