Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

Hi Nuno,

"The schematic is not very clear, not enough resolution."

- Don't browse it via Internet Explorer, save it and browse it using
PaintBrush; you'll get a much better view.
- I've just sent a BMP of the pic to you. You can improve that one, or send
me another schematic and I'll compare.

"I think that you should move the fuse to the AC part of the circuit"

- As I told Stefan, I think the fuse should be close to the ZNR and MOV
crowbar devices. But I am going to add another fuse on the AC side, I have
lots of spare holders. :D


"The LT1085 is rated for 3A and you want a power supply for 3A. Don't you
think it's to close?"

- Yes I do, I thought of that earlier today. I'm going to move up to the
LT1084 at least, same thing with the diodes.
- I also noticed I totally forgot the adjustment circuitry for the voltage
regulator.


"this subject doesn't fit in this group, OK?"

- several people in this group are building a PCB drilling station, hence
the title. We've been given permission to discuss stuff related with this
project here.


Robert
:)



-----Message d'origine-----
De : Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com] De
la part de Nuno Tavares
Envoyé : juillet 10 2005 16:25
À : Homebrew_PCBs@yahoogroups.com
Objet : RE: [Homebrew_PCBs] Drilling station 40V 3A power supply


Hi Robert,

The schematic is not very clear, not enough resolution. But of what I can
see, these points I noticed:
- I think that you should move the fuse to the AC part of the circuit
- The LT1085 is rated for 3A and you want a power supply for 3A. Don't you
think it's to close? What if there's an overload? Even without overload, if
you use a motor with this, or any other inductive or capacitive load, it's
starting up will not be an easy one. My advise is that you use a higher
current regulator, like the LT1084 or LT1083.
Same thing with the power supply diodes. Higher amperage rating is
better.

http://www.linear.com/pc/productDetail.do?navId=H0,C1,C1003,C1040,C1055,P128
3

- These regulators are adjustable ones. This means that they can be set to
supply a voltage from 1.25V up to whatever you choose with the resistors in
the adjustment pin. If you want 40V you cannot connect it to ground
directly.

If you whish, I can send you a better schematic of an 40V, 3A power supply,
with the LT's regulators or others. Or, you can send me the schematic with
much better resolution and I can help you to solve its problems.

P.S. use my private E_mail: nuno_t@..., this subject doesn't fit in this
group, OK?

Best,

Nuno Tavares

> -----Original Message-----
> From: Homebrew_PCBs@yahoogroups.com
> [mailto:Homebrew_PCBs@yahoogroups.com]
> On Behalf Of Robert Hedan
> Sent: domingo, 10 de Julho de 2005 20:17
> To: Homebrew_PCBs@yahoogroups.com
> Subject: [Homebrew_PCBs] Drilling station 40V 3A power supply
>
> Hi,
>
> I've just uploaded a schematic of a 40V 3A circuit that I put
> together. I've thrown in every security measure I could find in the
> DigiKey manual as an exercise. The file is in FILES / Power supplies.
> This link may (or may
> not) work:
> <http://f1.grp.yahoofs.com/v1/MHDRQjmKCjHN8hORzw6Lxapg3rQLHR9sg4BZ8ePemrCI
> Kl
> pX6E8d2Q1QnZ52WUfAGgpe1uV08UyZCt9sgF5IHEcaLLyziJI/Power%20supply/Drilling%
> 20
> station%2040V%203A%20steppers.JPG>
>
> Please let me know if I have design flaws, is the fuse rating high
> enough, components in series instead of parallel or vice versa,
> suggestions for additional security measures, improvements in
> filtering, etc.
>
> This is my first power supply and I don't want to have problems with
> it in the future. I also want to make it as robust as possible. A
> separate 5V circuit will power the logic circuitry, this is
> exclusively for the steppers.
>
> Robert
> :)
>
>
> Be sure to visit the group home and check for new Links, Files, and
> Photos:
> http://groups.yahoo.com/group/Homebrew_PCBs
>
> If Files or Photos are running short of space, post them here:
> http://groups.yahoo.com/group/Homebrew_PCBs_Archives/
> Yahoo! Groups Links
>
>
>
>
>
>
>
>
> Be sure to visit the group home and check for new Links, Files, and
> Photos:
> http://groups.yahoo.com/group/Homebrew_PCBs
>
> If Files or Photos are running short of space, post them here:
> http://groups.yahoo.com/group/Homebrew_PCBs_Archives/
> Yahoo! Groups Links
>
>
>
>

Be sure to visit the group home and check for new Links, Files, and Photos:
http://groups.yahoo.com/group/Homebrew_PCBs

If Files or Photos are running short of space, post them here:
http://groups.yahoo.com/group/Homebrew_PCBs_Archives/
Yahoo! Groups Links