Re: OLTC Measuring Peak Current

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "colin heath" <colin.heath4@xxxxxxxxxxxx>

hi robert,
            now thats a nice idea! what size stock was the stainless for
this as i work with tons of the stuff. also what lengths were needed for the
correct reading? i realise this will change with different grades but just
gives me a rough idea as to wether i can fit this into my project.
cheers
colin heath
----- Original Message -----
From: Tesla list <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Sunday, January 09, 2005 4:18 PM
Subject: Re: OLTC Measuring Peak Current


> Original poster: robert heidlebaugh <rheidlebaugh@xxxxxxxxxxxxxx>
>
> Adam: The simple way to measure peak current is with a shunt. A shunt is
not
> subject to frequency degridation like transformers. Low current shunts are
> relativly inexpencive, but high current shunts are hard to find and you
> usualy must make one.  Calibration is not dificult. Start with a low
> resistance such as a stainless steel bar. A 1" x 12" piece of sheet metal
> works for 100 Amps or less or over 100 amps for short durations. Put a
known
> current through the shunt of lets say 10 amps then move your amp meter
along
> the shunt to read 1 amp. Mark this point and rivet and solder a connector
to
> this point. You now have a 10:1 shunt. Sears sells a small role of pure
tin
> solder and acid flux in a small blister pack that solders stainless or use
> silver solder. To monitor fast time currents connect a scope to your
> connection point. NOTE I did not measure the resistance of the shunt. That
> requires a calibrated good quality bridge. Few people have one and it is
not
> nessisary. I have a 1000A shunt made of a piece of stainless round stock.
> calibrated to 6 places in a standards lab. You can make it  with what you
> have in your shop calibrated to the acuracy of your test equipment.
>        Robert   H
> --
>
>
>  > From: "Tesla list" <tesla@xxxxxxxxxx>
>  > Date: Mon, 03 Jan 2005 17:11:04 -0700
>  > To: tesla@xxxxxxxxxx
>  > Subject: OLTC Measuring Peak Current
>  > Resent-From: tesla@xxxxxxxxxx
>  > Resent-Date: Mon,  3 Jan 2005 17:20:33 -0700 (MST)
>  >
>  > Original poster: "Adam Horden" <adamhorden@xxxxxxxxxxxx>
>  >
>  > Hi All
>  >
>  > I am currently rebuilding my OLTC. I have rebuilt the controller and
>  > preliminary test show that it's working in constant BPS mode but the
>  > interrupted drive needs some work.
>  >
>  > I was wondering how I can go about measuring the peak current. I was
>  > planning to measure it on one side of the capacitor bank (not the
>  > neutral side)
>  >
>  > I don't have room in the low inductance layout for my ion physics
>  > current transformer (its about 6 inch dia).
>  >
>  > I was wondering how I can measure the peak current.
>  >
>  > Maybe a current transformer wound on a 1inch ferrite core?
>  >
>  > Adam
>  >
>  >
>  >