Re: EMI Filters

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Paul B. Brodie" <pbbrodie@xxxxxxxxxxxxx>

Steve,
I understand the misbehavior of the DVM. That is where I am confused. I 
thought the EMI filter would prevent the impulses from the ignition coil 
from "backing up" into the mains supply on the other side of the reverse 
wired EMI filter. Thanks.
Paul
Think Positive

----- Original Message -----
From: "Tesla list" <<mailto:tesla@xxxxxxxxxx>tesla@xxxxxxxxxx>
To: <<mailto:tesla@xxxxxxxxxx>tesla@xxxxxxxxxx>
Sent: Thursday, May 05, 2005 11:46 PM
Subject: Re: EMI Filters

> Original poster: "S&JY" 
<<mailto:youngsters@xxxxxxxxxxxxxxx>youngsters@xxxxxxxxxxxxxxx>
>
> Paul,
>
> Many digital VOMs misbehave when the waveform is anything but a sine wave.
> When impulses are flying around from spark discharges, many DVMs won't
> function at all.  If you use an analog meter, you will see that your
> measurements are what you would expect.
> --Steve Y.
>
> ----- Original Message -----
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> To: <<mailto:tesla@xxxxxxxxxx>tesla@xxxxxxxxxx>
> Sent: Thursday, May 05, 2005 11:20 AM
> Subject: EMI Filters
>
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> > Original poster: "Paul B. Brodie" 
<<mailto:pbbrodie@xxxxxxxxxxxxx>pbbrodie@xxxxxxxxxxxxx>
> >
> > I have a 20A EMI filter wired in reverse between the wall outlet and my
> > variac. I have a volt meter attached to the variac outlet.
> >
> > I was driving one of my ignition coils with a 600 watt dimmer in series
> > with a 2mF cap. As I powered up the variac, I could read the voltage
> > increasing on the volt meter all the way up to 120V. When I turned up the
> > dimmer, the voltage indication on the volt meter went haywire when the
> coil
> > began sparking. If I drew the ground away from the HV output, the volt
> > meter would stabilize as soon as the sparks stopped.
> >
> > What have I missed here? This isn't normal, is it??!! Could the EMI filter
> > be bad?
> > Paul
> > Think Positive
> >
> >
> >
> >
> >
>
>