[Milsurplus] 400 Hz Static Inverter

[Dave Maples]

All: A long time ago I built a 400-Hz power supply out of an old PA
amplifier, a transformer, and a 400 Hz oscillator I made from a 555 timer
chip and a 3-stage RC lowpass filter.  It made a dandy 400 Hz supply for an
ARC-38A.  For single-phase 400 Hz power, that's the way I'd go if the power
requirement were modest (less than 100 watts or so).

If the requirement is 3-phase power, three D-type flip-flops in series, with
the not-Q output of the last one tied to the D input of the first, a common
clock signal at 2400 Hz (555 timer again), and a reset to ensure that all
three flip-flops are reset before the clock starts should produce a very
good 400 Hz three-phase signal.  Running each output through the RC filters
as described would generate very nice 400 Hz sinewaves 120 degrees
apart...you'd have to find three PA amplifiers, though.

A more sophisticated approach would be to use an Arduino board or similar to
produce three 2-bit-wide outputs to create 400 Hz 3-phase power.

All this is presuming you want to spend the time to do all this.  The motor
controller might make more sense.

Thanks,
Dave WB4FUR

-----Original Message-----
From: milsurplus-bounces at mailman.qth.net
[mailto:milsurplus-bounces at mailman.qth.net]On Behalf Of Francesco Ledda
Sent: Sunday, April 29, 2012 10:53 PM
To: KD7JYK DM09
Cc: milsurplus at mailman.qth.net
Subject: Re: [Milsurplus] 400 Hz Static Inverter


Who do you want to modify it? Many have single paste input and 3 phase
output. They are ready to go.

Sent from my iPad

On Apr 29, 2012, at 9:13 PM, "KD7JYK DM09" <kd7jyk at earthlink.net> wrote:

> : Yes. That's exactly what I'm considering, but I'd like to find a
> : brand/model that is known to be modifyable. Prints would be a real
bonus.
>
> I didn't find anything on the web, although they used to be everywhere -
ten
> to fifteen years ago.  The only printout I have is buried, never to be
seen
> again.
>
> Kurt
>
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