Re: mysterious coil failure / M and k Measurement (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Sun, 04 Nov 2007 08:45:21 -0800
From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: mysterious coil failure / M and k Measurement (fwd)

Hi All,

I fixed the wording with the M and K measurement and replaced the gif 
with a pdf (couldn't find the original so I recreated it) and listed it 
on my download page. I left the snubber out this time.

http://www.classictesla.com/download/M_and_K.pdf

Take care,
Bart
> Tesla list wrote:
>> ---------- Forwarded message ----------
>> Date: Thu, 1 Nov 2007 03:04:59 +0100
>> From: Kurt Schraner <k.schraner@xxxxxxxxxxx>
>> To: Tesla list <tesla@xxxxxxxxxx>
>> Subject: Re: mysterious coil failure / M and k Measurement (fwd)
>>
>> Hi Gary Lau,
>>
>> sorry for not having been clear enough! Of course you are right: when 
>> I wrote "between the mains AC line and the rest of the circuit", I 
>> didn't mean to remove the ballast. Of course, the ballast resistor 
>> should be adapted to limit the current of the transformer in use. In 
>> my case, I had a transformer with 12V/30A, and a current limiting 
>> resistor, limiting the current to 10A or 15A. With the transformer in 
>> place, it's then feasible to move the primary tap, without even 
>> switching off the supply. My coupling k mesurements zipped Excels can 
>> be downloaded from:
>>
>> http://home.datacomm.ch/k.schraner/spreadsheets.htm
>>
>> Having verified the reliability of Paul Nicholson's ACMI and Mark 
>> Rzeszotarski's M_and_k programs, nowadays I usually abstain from 
>> performing the measurements, just relying on the calculations, which 
>> are within the error limits of the measurements.
>>
>> Best regards, Kurt
>>
>> Tesla list wrote:
>>  
>>> ---------- Forwarded message ----------
>>> Date: Wed, 31 Oct 2007 15:39:33 +0000
>>> From: "Lau, Gary" <Gary.Lau@xxxxxx>
>>> To: Tesla list <tesla@xxxxxxxxxx>
>>> Subject: RE: mysterious coil failure / M and k Measurement (fwd)
>>>
>>> Hi Kurt:
>>>
>>> It's a worthy goal to modify this measurement technique to eliminate
>>> the electrocution hazard.  But it's not clear to me that it's
>>> possible to achieve this without the use of a resistive ballast such
>>> as the hair dryer.  Placing a 6 volt transformer secondary across
>>> most TC primary coils would be essentially a short circuit and exceed
>>> the transformer's current rating.  Even if the transformer was driven
>>> with a Variac, I would worry that there might still be some
>>> non-linear behavior driving a near short-circuit, resulting in
>>> non-sinusoidal waveforms and inaccurate measurements with common
>>> DMM's.
>>>
>>> Or, are you proposing to still use a suitable (?) ballast on either
>>> the primary or secondary side of the xfmr, and make sure that the
>>> xfmr secondary current remains well below its rating?  What is the
>>> minimum TC primary current that results in an induced TC secondary
>>> voltage high enough to stay above the noise?
>>>
>>> Regards, Gary Lau
>>> MA, USA
>>>
>>>    
>>>> From: Kurt Schraner <k.schraner@xxxxxxxxxxx>
>>>> To: Tesla list <tesla@xxxxxxxxxx>
>>>> Subject: Re: mysterious coil failure / M and k Measurement
>>>>
>>>> The safety concerns, regarding the circuit at Bart's site:
>>>> http://www.classictesla.com/download/M_and_k_Measurement.gif
>>>> can be eliminated, using a downstep transformer (i.e. Vout=6...12V;
>>>> some Amps), inserted between the mains AC line and the rest of the
>>>> circuit. And voltage may optionally be adjusted, by using a variac.
>>>> This allows much quicker measurement at different taps of the
>>>> primary.
>>>> BTW, I'm also taking the measurements without the RC combination
>>>> accross the secondary.
>>>>
>>>> Regards, Kurt
>>>>       
>>
>>
>>
>>
>>
>>
>>
>>   
>