Re: [CAD_CAM_EDM_DRO] Re: looking for a 20vac transformer resource

----- Original Message -----
From: "caudlet" <thom@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Saturday, February 19, 2005 11:46 PM
Subject: [CAD_CAM_EDM_DRO] Re: looking for a 20vac transformer resource


>
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Monte" <montejw@e...> wrote:
>>
>> I have a power supply that outputs 36vdc (24vac transformers)and I
>> want to get down to 30vdc. A 20v transformer would get me 28vdc,
> if I
>> have the math right, which is close enough. Where can I get one (or
>> 2) of these. I want to drive the 4 axis Xylotex driver board and
> some
>> 250 oz in steppers on my Taig mill.
>>
>> Or a 24-30vdc power supply would work too, if the price is right.
>>
>> Thanks,
>> Monte
>
> I JUST went through this same exercise. I dug through a stack of old
> linear supplies (I can't bring myself to throw away transformers) and
> found a 5 amp 15 regulated supply. The Raw DC was about 27 volts.
> The primary was tapped for low ac so I used that tap and
> wahla...30VDC on the nickle! I just tapped off the big filter cap.
> If you can find a cheap 15VDC regulated DC linear supply I'll bet you
> can get close to your voltage. You don't have to disconnect anything
> and there were spare lugs on the output terminal strip so now I have
> 30VDC (unregulated) and 15VDC regulated.
>
> A 12V supply will be too low and a 24 will be too high. The 15 was
> just right. Reason: The designer has to be able to maintain
> regulation down to low line (brown out) of 90VAC. It takes around 5
> volts more in than out in a traditional series pass circuit figuring
> in all of the voltgae drops, so he needed 20V at 90VAC. At 120VAC
> that works out to about 26.6 VOlts. The booster tap on the primary
> (for running in cronically low line conditions) boosts the output
> about 10% in RMS volts or about 14% (30.4 VDC) which almost exactly
> what I have.
>
>
>
>
>
>
>
> Addresses:
> FAQ: http://www.ktmarketing.com/faq.html
> FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
> Post Messages: CAD_CAM_EDM_DRO@yahoogroups.com
>
> Subscribe: CAD_CAM_EDM_DRO-subscribe@yahoogroups.com
> Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@yahoogroups.com
> List owner: CAD_CAM_EDM_DRO-owner@yahoogroups.com, wanliker@...,
> timg@...
> Moderator: pentam@... indigo_red@... davemucha@...
> [Moderators]
> URL to this group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO
>
> OFF Topic POSTS: General Machining
> If you wish to post on unlimited OT subjects goto:
> aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it
> if you have trouble.
> http://www.metalworking.com/news_servers.html
>
> http://groups.yahoo.com/group/jobshophomeshop I consider this to be a
> sister site to the CCED group, as many of the same members are there, for
> OT subjects, that are not allowed on the CCED list.
>
> NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM.
> DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........
> bill
> List Mom
> List Owner
>
>
> Yahoo! Groups Links
>
>
>
>
>
>
>
>