Re: [TCML] Depot NST Measurements

["Phillip Slawinski" <pslawinski@xxxxxxxxx>]

Ahhh, I see.  So you don't have to have a fancy clamp meter?

On Sun, Jun 29, 2008 at 8:25 PM, bartb <bartb@xxxxxxxxxxxxxxxx> wrote:

> Hi Phil,
>
> When the HV side of the secondary is shorted (short circuit current), there
> is no voltage because it's shorted out. Measuring the short circuit current
> is simple. Set your digital meter to read about a 200mA scale. With the
> meter set to measure current (and leads in the correct socket), connect each
> lead across the HV output terminals. Then apply input power. That's all
> there is to it.
>
> However, there are precautions. NEVER disconnect or connect the meter leads
> with power applied. This will give you a little shock and also kill your
> meter. As long as the output is shorted, there is no voltage across the
> output terminals. But as soon as you disconnect it, then the full voltage is
> felt and will immediately arc to the lead you disconnected.
>
> Just make sure the meter is set and connected before applying power. And
> turn power off before connecting. I know all that appears common sense, but
> when making these type of measurements, it's easy to get out of step and
> make a mistake.
>
> Take care,
> Bart
>
>
> Phillip Slawinski wrote:
>
>> Interesting,
>>
>> I have two questions.  First did you bother to measure short circuit
>> voltage?  Second what did you use to measure secondary current?
>>
>> On Sun, Jun 29, 2008 at 4:44 PM, bartb <bartb@xxxxxxxxxxxxxxxx> wrote:
>>
>>
>>
>>> Hi All,
>>>
>>> For someone not to long ago I mentioned I would remeasure my depotted
>>> 12/60
>>> when my new hv probe arrived. Well, I had a chance today.
>>>
>>> I performed open and short circuit measurements. Using a variac, I
>>> adjusted
>>> the NST input voltage in 10V increments up to 140V input.
>>>
>>> Here's the raw data table:
>>> http://www.classictesla.com/temp/DepotNST_RawData.gif
>>>
>>> Here's a graph of input to output voltage (very linear):
>>> http://www.classictesla.com/temp/DepotNST_VinVout.gif
>>>
>>> Here's a graph of short circuit current:
>>> http://www.classictesla.com/temp/DepotNST_Is.gif
>>>
>>> And finally, here's a graph of the NST's coupling coefficient:
>>> http://www.classictesla.com/temp/DepotNST_K.gif
>>>
>>> So, for my NST, it became extremely beefy with 1/2 the shunts removed. I
>>> don't know what to say about others who have only doubled their secondary
>>> current. My NST ended up at a little over 200mA (for where I normally
>>> run).
>>> Obviously, I could send it to the grave if I pushed it too hard. But
>>> then,
>>> I've also ran a 30 minute continuous run with it pushing 5 foot sparks
>>> and
>>> there were no hiccups. Anyway, the data table speaks volumes.
>>>
>>> Take care,
>>> Bart
>>> _______________________________________________
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>>> http://www.pupman.com/mailman/listinfo/tesla
>>>
>>>
>>>
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