Re: Input Power Measurement

To: tesla-at-poodle.pupman-dot-com
Subject: Re: Input Power Measurement
From: Tesla List <tesla-at-stic-dot-net>
Date: Thu, 29 May 1997 07:48:47 -0500
Approved: tesla-at-stic-dot-net
Subject:  Re: Input Power Measurement
  Date:  Wed, 28 May 1997 05:43:03 +0000
  From: "John H. Couture" <couturejh-at-worldnet.att-dot-net>
    To:  Tesla List <tesla-at-pupman-dot-com>


At 01:19 PM 5/27/97 +0000, you wrote:
>Subject:       Re: Input Power Measurement
>       Date:   Tue, 27 May 1997 06:20:51 -0700
>       From:   Bert Hickman <bert.hickman-at-aquila-dot-com>
>Organization:  Stoneridge Engineering
>         To:   Tesla List <tesla-at-pupman-dot-com>
> References:   1
>
>
>Tesla List wrote:
>> 
>> Subject:     Input Power Measurement
>>        Date: Mon, 26 May 1997 23:42:39 -0700
>>        From: Skip Greiner <sgreiner-at-wwnet-dot-com>
>> Organization: Greiner, Ltd.
>>          To:  tesla list <tesla-at-pupman-dot-com>
>> 
>> Hi All
>> 
>> It is obvious to all that any given transformer can be run in excess of
>> its rating. Thus, a 1kva transformer may be run with 2kva input and
>> live. This does not mean that the TC is being run at 1kva since the
>> transformer is rated at 1kva.
>> 
>> How can the actual input power to the TC be measured????????
>> 
------------------------------------- snip

>> Any suggestions would be appreciated.
>> 
>> Skip
>
>Skip,
>
>While precise measurement of input wattage is quite difficult due to the
>non-sinusoidal input currents, the wattmeter should provide a useful
>relative comparison when the systems are run at similar break rates. 
>
>-- Bert --
>
------------------------------------------------------------

  Skip, Bert -

  Measuring the input power to a Tesla coil is not an easy job if you
want
accuracy. All standard voltmeters, ammeters, and wattmeters are accurate
only with sinusoidal currents and TC currents are not sinusoidal. Note
that
all wattmeters are instantaneous. Hot wire ammeters are frequency
sensitive
because of the wire motion. 

  However, it is possible to build electronic metering devices to do the
job
if you have the capability. Because some electrical loads on the
electric
power company lines are creating large non sinusoidal currents, power
companies are using electronic metering.

  Different types of transformers with the same rating will do a better
job
under certain conditions. For example, you will get longer sparks with
lower
percent impedance transformers. Also, using large transformers at lower
than
nameplate rating will give you a more efficient less watts per foot of
spark. There are many possibilities to increase the efficiency of a TC
system. To measure the efficiency, I use the efficiency graph that I
described in a post several months ago.

  John Couture