Re: OLTC Measuring Peak Current

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: robert heidlebaugh <rheidlebaugh@xxxxxxxxxxxxxx>

My small shunts are 12" of 18 ga 302 stainless. My meadium shunts are 14" of
3/8 203 round stoch amd my largest shunt is a 2 ft 3/4 round stock cut in
half length wise. Inductance is no problem unless you fold the stock into
less length. That adds inductance . The streight rods do not cause an
inductance  problem unless the length is 1/10 of the wave length.
      Robert    H
--


> From: "Tesla list" <tesla@xxxxxxxxxx>
> Date: Sun, 09 Jan 2005 12:07:01 -0700
> To: tesla@xxxxxxxxxx
> Subject: Re: OLTC Measuring Peak Current
> Resent-From: tesla@xxxxxxxxxx
> Resent-Date: Sun,  9 Jan 2005 12:09:31 -0700 (MST)
>
> 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
>>>
>>>
>>>
>
>