Re: Current Transformer problems

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "R Heidlebaugh by way of Terry Fritz <twftesla-at-qwest-dot-net>" <rheidlebaugh-at-zialink-dot-com>

on 11/27/01 7:57 AM, Tesla list at tesla-at-pupman-dot-com wrote:

> Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <jimlux-at-earthlink-dot-net>
> 
> Do you have a termination on the sense coil? Or, are you just running some
> coax from the sense coil to the scope input (nominally 1 Meg, 20 pF)
> Have you tested it with a resistive load (i.e. run AC  to a lightbulb,
> instead of the TC, and look at the current waveform.)?
> 
> ----- Original Message -----
> From: "Tesla list" <tesla-at-pupman-dot-com>
> To: <tesla-at-pupman-dot-com>
> Sent: Monday, November 26, 2001 7:51 PM
> Subject: Current Transformer problems
> 
> 
>> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <Mddeming-at-aol-dot-com>
>> 
>> Hi All,
>> This question is for anyone with experience in use of current
>> transformers and O-scopes.
>> I made a quick current transformer by winding 20 ft (~150 turns) of #20
> magnet
>> wire around a 1-inch ID ferrite toroid When I hook it to my scope I get a
> wave
>> pattern that is very distorted with overtones, 2f, 4f, etc., and pulses of
> HF
>> ringing.
>> This is on the inlet side of the control box without the coil or cap
> attached.
>> The entire lab is lined with grounded wire mesh except the front door.
>> 1. What am I doing wrong?
>> 2. How can I fix it?
>> Matt D.
>> 
>> 
> 
> 
> 
The current/voltage you are interested in is very low frequency so shunt
your coil with a capacitor (.1 to 5 uf ) be shure one side of the coil is to
test ground. Put a single strand of current carring wire through the center
of your toroid (one side of your supply line) This should work.
   Robert  H