[Milsurplus] Inverter idea

[John McCarty]

Marty, Jack and all...


	I've been working this issue part time also, looking for a to power up a GP-7.
Now, were lucky enough to have a professional power supply designer as a member
of our local radio club. She was giving a very good presentation on switching
power supplies during one meeting. After the presentation, I asked her how could
I buy/steal/wind a power xfmr for the GP-7. Her answer, why would I do that, the
rig has a perfectly good xfmr already, use it. What she was saying is use the
power transfomer (800 cps) in the transmitter like the xfmr in a switched power
supply. Think of it this way. Bridge rectum-fry the 110 ac out of the wall
(fuses before the bridge would be a good idea). Take the hump d.c. from that and
send it to the xfmr though switching xsistors. Since the xfmr in the GP-7 is not
centered tapped, you might have to use a couple of caps in series accross the
line as the return for the xsistors. There may be devices available for this
application already, we just have to find them. Like I said, just starting down
this road. It'll have to wait until AFD and F.D. projects are off the work bench
before I can take another run at it. And like ac/dc radios of old, shielding for
saftey is very importand.





											73



												John n9hrt 

Marty Reynolds wrote:
> 
> .
> >
> > Has anyone tried to see if these inverters can be
> > altered to make 400 cycles instead of 60?
> >
> > Jack
> 
> OK, I just looked into a 175W GE.  3 16-pin dip ICs, one
> 20 pin.  Lotsa glue pieces.
> 
> This was 2nd visit, 1st being a year back.  Again I felt
> like the nude in the sculpture looking @ the skull saying
> "Alas poor Yorrick."
> 
> These modern inverters are some kinda neat.  They're PWM
> to deliver 115VAC rms independent of load.  Waveform is
> series of steps that approximate a sine.  Each step made
> of lots little PWM interior spikes.  And they're always
> delivering ~300V p-p.
> 
> If you find the answer Jack, call - don't write!
> 
> Makes you wonder how they come to market so cheap
> 
> Time flies like an arrow
> 
> Fruit flies like a bananna
> 
>    Groucho
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