[simpits-tech] Wiring of POT and EPL

[Martin Ingold]

I understand what you say... I don't say it doesn't work the way you say it does, but I say
that all my sim instruments don't need 400Hz, but +-15V and most do have synchros in... well at
least they are labeled as that, with the 26V 400Hz on the casing as you said.
You can see a pic of such a thing here:
http://www.f16cockpit.net/INSTR1.jpg
This is the electronics of a SIM INSTR MODE panel for the F-16 Made by Malwin.
I think you can see on the synchro that there's 400Hz written. I have to feed the chip there
with +28V, and do get a clean output signal on 4 wires (most likely sin/cos).
If you need more, I can take pics of other stuff with synchros in too... but as said, the
instruments all operate off of +-15V. Even the HSI, which has many synchros (about 6 IIRC) only
needs +-15V and a sin/cos input signal to be driven....

Martin

Gene Buckle wrote:

> Martin, there is _no_ such thing as a DC synchro.  DC cannot provide the
> sine waves that the device _requires_ to operate.  The only way you could
> even think of it working is if you used a high frequency square wave and
> all that is is AC with "edges".  At 60Hz AC a synchro will function, but
> it "buzzes" and gets warm very quickly.  At straight DC it would probably
> flash one of the six internal coils to slag.
>
> A synchro functions by moving a stator to a "null" point.  This null point
> occurs when two sine waves cancel each other out.  For this to happen, the
> input current to the device MUST be AC.  There is no way around it.  This
> is how a synchro resolver or reciever work.  A syncro transmitter actually
> changes the null point when you manually rotate the stator.  For example,
> you can hook a resolver directly to a transmitter (with the 400Hz AC
> supply in the middle) and watch the shaft of the resolver move in perfect
> synchronization with the stator (shaft) in the transmitter as you turn it.
>
> Do you have a picture of this device you have?  I'd like to see it.
>
> tnx.
>
> g.
>
>  On Fri, 28 Feb 2003, Martin Ingold wrote:
>
> > Well yes, they are all labeled with 400Hz on the outside. Though they don't use it..
> > believe me. Pin outs of the manufacturers of the instrument show DC voltage used too....
> > there's absolutely no need for 400Hz on ANY Sim-Instrument I have, and yes, they DO have
> > Synchros in them.... I was worried about needing to use 400Hz when I first saw them...
> > Pin-Outs and "reverse engineering" of circuits teached me the opposite... looks like they
> > are avoiding that stuff for the simulators...
> >
> > Martin
> >
> > Gene Buckle wrote:
> >
> > > > Not quite... the sim stuff that uses synchros feeds them with DC
> > > > voltage, which causes the synchro to spit out a sin/cos (I think)
> > > > signal.... The instruments and stuff I have from Sims have lot's of
> > > > synchros in, and not one of them needs 400Hz or makes that current
> > > > internaly.
> > >
> > > Every synchro I have is rated for either 28 or 115 volts AC at 400Hz.  No
> > > commercial flight simulator I've ever seen drives a real synchro on DC.
> > > They way they're wired precludes them from producing a correct signal on
> > > DC. (DC has no sine wave, which the synchro manipulates or is manipulated
> > > by)  If it's working on DC, then it's not a synchro.
> > >
> > > g.
> > >
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