Re: [CAD_CAM_EDM_DRO] DC power supply questions

I bought a 3 kw transformer from the surplus center for $129. It can be
wired several ways. The way I wired it I got 164VDC when rectified to DC. It
is an isolated transformer. Brand New. Great price.
Dan Mauch
Camtronics Inc
www.camtronics-cnc.com
www.seanet.com/~dmauch
low cost stepper motors , cases for gecko drives

----- Original Message -----
From: "Michael Larson" <mykow@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Thursday, June 23, 2005 4:02 PM
Subject: [CAD_CAM_EDM_DRO] DC power supply questions


> Hi all, I'm trying to assemble an unregulated DC power supply that will
> run at about 135V and 3kW total. The bridge rectifier and capacitors
> are no big deal to source but I'm having a problem finding a transformer
> big enough. A couple questions:
>
> Can I use a variac transformer if it's rated to 3kW? Searching the
> archives tends to say that this is *not* an isolation transformer and so
> I should add one of those for safety. Would a 3kW variac + 3kW
> isolation transformer do the job? Should I put the isolation
> transformer on the supply side or the load side of the variac? Are most
> 240->120V step-down transformers isolation transformers? Am I going to
> get bad voltage fluctuations because of the nature of the variac?
> Should I skip all this and keep trying to find that mystical 90VAC 3kW
> toroidal transformer under $300?
>
> Are there any special problems with running multiple capacitors in
> parallel to get the desired capacitance?
>
> Thanks, this group is amazing.
> Michael
>
>
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