RE: [CAD_CAM_EDM_DRO] Voltage Regulators or Diodes to drop voltage?

Hans,

But it is not macho to not run at the absolute limit <g>

Seriously, you make a great point. This comes up regularly where the
poster feels they need to be right at the absolute voltage limit of the
drive. I am with you and feel it is far more prudent (not to mention
reliable) to run below the limits. I was just playing with the same
drive as the poster and running it on 30 vdc. Works great and no worry
about a voltage spike on the line side.

Tim
[Denver, CO]
Sherline products at Deep Discount
Mach1 & DeskCNC with credit card ordering
www.KTMarketing.com/Sherline

> -----Original Message-----
>
>
> Three volts too high on an Unregulated 35 Volt supply ! If
> your final electronics cannot tolerate any more than 35
> Volts, then that's where your problem is. No one should run
> electronics on 35 Volt unregulated supply IF it only
> tolerates 35 Volts, bad practice, and will cause problems.
>
> Assuming you are in the USA. Assume a AC supply of 110-115
> Volts. and if you "tweak" for 35 Volts DC output (I assume
> under full load ) Come to think about it.... 3 Volts swing on
> an unregulated supplies doing 7 Amps from full load to light
> load is good.... ! Then a small change in Input Supply and
> you are back to square one.... I think power companies are
> allowed to deliver your AC with +- 10% variations.
>
> Anyway, if you are determined to tweak it, you can try the
> following...
>
> Did you wind the transformer ?
>
> If there is still space you can add windings to the secondary
> equal to 2-3 Volts and connect that extra winding in Anti
> Phase. In the "old days" this was called "bucking" turns or
> similar. That will Subtract the extra Voltage. These extra
> windings can be wound on top of or outside the existing
> windings. When I say outside I don't mean around the iron
> core, I mean on the bobbin where the other windings are. As
> you only require 2-3 Volts I expect it will only take a few
> turns and it may be quicker to thread them by hand.
>
> Diodes in series will work, you mentioned 7 Amps . That means
> 7A * 3V = 21 Watts !
>
> Regulators are fine but 7 Amp 35 Volts Linear versions are
> few and far between, you could build your own using discreet
> components or spend half your life building a switch mode PSU.
>
> If you did wind the transformer, in future add some taps in
> the primary to allow for small adjustments. You may have seen
> these on commercial transformers with extra primary winding/s
> (not tap) just for that reason.
>
> My final advice is : Don't run critical electronics so near
> to maximum voltage on unregulated supplies.....
>
> Best regards
> Hans W