On Nov 12, 5:08*am, clifford wright
wrote:
philo wrote :









On 11/04/2011 10:17 AM, JIMMIE wrote:
I came by what appears to be a power supply module from some old
military gear. It uses a synchronous vibrator unless my analysis of
the circuit it way off. My plan is to build a circuit to replace the
vibrator with a couple of power FETs driven by a 555 osc and a bridge
rectfier to handle rectification of the output. I was wondering if
there were any circuit designs around before I started to reinvent the
wheel. Also what freqency do they use. Seems like I heard 100Hz at one
time but I dont trust my memory on something I learned 40 years ago.
Any help would be much appreciate.

Jimmie

I believe that military equipment was 400 hz...

(if so, the xfmr would not be usable at 60hz)

If it's in working condition it would be easy enough to check.

Well the 400 Hz is a bit odd for a vibrator pack.
Are you sure that the supply wasn't designed for 400Hz AC?
That could be explained by use in Aircraft where 400HZ supply
is quite common. Most mechanical vibrators actually do run at
about 100 Hz. I have built solid state replacement for several
and they all had that in common.
Of course the builder could have used a 400 Hz transformer, but that
wouldn't match a normal vibrator at all.
BTW the old Marconi spark transmitters (like on the Titanic) used a 400HZ
tuned keying relay to protect the operator. Just like a modern zero
crossing switch!
Cliff wright ZL1BDA ex G3NIA

Clifford, would you share schematic of the one you built. Im using my
function generator to drive a flip-flop to drive a pair of power FETs.
Seems to be working but I would like to see someone elses design. BTW
this thing seems to work from 50 to 500 HZ. There is also a winding on
it that may be an input to run it off the mains. Not sure of that yet
as I have never seen one before.

Jimmie