[Milsurplus] Chokes

[Marty Reynolds]

Rick, hi

I see no one's written, so here goes.

On ur ART-13 p-s project.  This guy thinks a little engineering
better than a lot of 'good practice' discussion.  Sorry there won't
be 'this is it' conclusions here.  Instead a vector on how to DIY
(do it urseff)

First you MUST use choke input on HV if 866s employed.  However
I think there's little B+ load change with modulation since the 811s
were run AB1, not class B, to keep the dyno speed mostly constant.

Further the LV B+ is very constant

So swinging chokes unneeded for either supply.

Have '57 Radio Amateur's Hbk here in lap & Chap. 7 tells what's
needed for a choke input p-s design.  Simple formula

     Lh = Evolts/Ima

gives minimum inductance for choke input regulation effect.  Getting
ripple where you need it is another story and probably beyond abilities
of 4 & 8 mfd oil filled cap.s that "are a must."

Don't have a DY-17 in lap to reveal p-s needs.  But do note
that simple graphical interpolation will give you C values
when loads known.

You can still use the oil-hulks above chassis for looks.  But
electrolytics under chassis would be best in 2006.  Of course you
may have to, say, series groups of four 450V jobs for the hv.

Durn I hate to hear a TX-1 got parted out - I like those Apaches

And in closing, don't forget to delay HV xfrmr after 866 filament
turn-on

   Marty

PS... these notions were employed to build the 1, 2, or 3 RBx power
      supply on LST325.  Regulation on 120, 240, 360 ma loads was
      better than 2%