Cheap Power Supply was Re: low cost drivers

I ordered the transformer and was surprised how fast it came up to
Canada. If you purchase it, you will most likely want to connect the
secondary windings together (connect 0 to 28V) to obtain the 56VAC.

The nice thing about this particular transformer is that it has
several taps, there is a 14VAC tap that can be used for +12VDC or
+5VDC power for logic or relay driving.

I had trouble ordering the rectifier, but had little difficulty
finding a replacement number from DigiKey. If anyone is interested,
I can look up the part number...

Fortunately, I have access to capacitor hardware for mounting to
chassis. This might be a consideration if you are building this
power supply (it is a metal bracket that squeezes the cap firmly,
while supplying mounting flanges to fasten to the case).

For anyone new to electronics, I would highly recommend installing a
fuse on the primary side of the transformer.

I am using the AC Connectors of an unused PC Power Supply so standard
computer power cables can be used with my controller.

Hope this helps anyone building the supply.

Steven

--- In CAD_CAM_EDM_DRO@y..., "mariss92705" <mariss92705@y...> wrote:
> Hi,
>
> I went to this link and noticed a 56 volt AC, 8A transformer for
$20.
> Add a 10,000 uF / 100VDC cap (DigiKey # P10040-ND $15.25 each), a
> 25A, 400VDC bridge rectifier (DigiKey # GBPC1506-ND $2.88 each) and
> you have a nice 75VDC @ 8A, 600W power supply for about $38. You
> could do it for less if you got the cap surplus somewhere.
>
> Mariss
>
> --- In CAD_CAM_EDM_DRO@y..., "rekmac" <rkonnen@t...> wrote:
> > Thank you for the feed back, it is being very helpful. I still
> > haven't firgured the higher voltage ,power resister thing yet
> though.
> > A couple of other things to ask or add. I found out the steppers
I
> > have are Bipolar if I understand it right, 4 wire. What ideas on
> > drivers for these? Also found a place that may hay a good source
> for
> > surplus and a good selection for power resistors. You have to
call
> > though, they don't list much on their site.
> > http://www.skycraftsurplus.com/
> > Thanks,
> > Richard