Re: [CAD_CAM_EDM_DRO] Re: Power Supply-- more questions

Jarrett,

You do not need 25 times. I would go with a 48 VAC transformer which would
give you about 67 volts DC.

Your Gecko drives will not draw the full 24 amps. You need to derate it by a
factor of about .6 which brings it down to about 16 amps.

I would go with one 18,000 mfd capacitor.

Bob Campbell
Bob Campbell Designs
www.Campbelldesigns.com
Mach 2/3 breakout boards
Relay boards
Spindle Speed boards
Stepper motors
Plasma Torch Height control

----- Original Message -----
From: "Jarrett & Heidi Johnson" <hjjohnson@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Wednesday, January 04, 2006 12:47 AM
Subject: [CAD_CAM_EDM_DRO] Re: Power Supply-- more questions


> Well now that the holidays are over.. time to get back to work. I've got
> my steppers planned out. I finally settled on a bit larger units than
> origianlly planned. 3.5v and 6.0A /phase parrellel producing 1160 oz-in.
>
> Anyway I was wondering if someone could just double check my numbers on
> this power supply before I order the parts.
> I can't quite get 25 times my stepper voltage as that would put me over
> the Gecko 80v rating. So I'm shooting for 78vDC to the drives. Therefore
> 78/1.4=56vAC 6.0A x 4 steppers =24A.
>
> My Capacitor's should be C=(80,000*24)/78 C=24615uF I found some Cap's
> from DigiKey and here's the spec's
> [page 977 in the Canadian Cataloge--if anyone feels like looking it up]
>
> 100v (working) 125v Surge.
> 18000uF
> 0.016ESR @120Hz -20Deg C [No idea what this is]
> 12.85 R.C. (A) @ 120Hz, 85Deg C [or this]
>
> I have no idea if the above will work.. ok.. or if I'm totally off base.
> They want $41 CAD each. I would need two of them wired in Parrellel??
> Also wondering about what make [material] the proper CAP should be made
> from.. as there seem's to be several choices? What got me looking at these
> ones was simply that they "looked" like one's I've seen in others project
> pictures.... The are Panisonic and are called "Computer Grade Capacitor's"
>
> Next on the list is the Bridge Rectifier.. I don't think there is alot of
> science for these, I chose one, 35A @ 100V, 400A Max surge, 10.0 uA Max
> reverse current, 1.1V Max forward volt [peak] They want $4 CAD. [ Digikey
> also]
>
> Is there anything else I missing? I seem to remember someone putting
> various other Resistors and what not in theirs.. ??
>
> Thanks in Advance!
> Jarrett Johnson
>
>
> [Non-text portions of this message have been removed]
>
>
>
> 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
>
>
>
>
>
>