Re: Input power measurement

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

Original poster: "Steven Ward by way of Terry Fritz <teslalist-at-qwest-dot-net>" <srward16-at-hotmail-dot-com>

Oddly,

I was just working on a 15/60 system.  I couldnt tune it with my 12 turn 
primary, so i increased the capacitance to about .016uf.  Then the thing 
blew out a 15A slow fuse!  So does the LTR actually pull out more power?
And if so, 5A or more(like in my system)?  Its strange that i have been 
able to run my 15/120 system on the same line!!  So im also stumped about this.

Steve Ward.

PS, i run my 7.5A variac at 20+ amps quite often.  I wouldnt worry about a 
10A variac being stressed from a 12A load.  Unless its one of those newer 
wussy ones ;)




>From: "Tesla list" <tesla-at-pupman-dot-com>
>To: tesla-at-pupman-dot-com
>Subject: Re: Input power measurement
>Date: Sat, 08 Mar 2003 16:00:33 -0700
>
>Original poster: "Chris Roberts by way of Terry Fritz 
><teslalist-at-qwest-dot-net>" <quezacotl_14000000000000-at-yahoo-dot-com>
>
>
>I actually just had a problem that is similar to what you are talking 
>about. I was running my 9/120 NST coil at the school yesterday and all of 
>a sudden, the coil stopped running. Scared the crap out of me, thinking I 
>killed my transformer. Instead, the 12 amp fuse on the variac gave out. 
>Odd, seeing as the NST should only pull 9 amps. Does that mean I might be 
>overstressing my 10 amp variac? I am using a LTR cap on my coil. I 
>remember hearing (this may or may not be true) that an LTR cap "pulls" 
>more energy out of the transformer. If this is true, then that's probably 
>the reason for my coil. It might be the along same lines for your 
>transformer. Either that, or the NST might have had some shunts removed. 
>Is there any way you could measure the output of the NST?
>
>  Tesla list <tesla-at-pupman-dot-com> wrote:
>Original poster: "Skip Greiner by way of Terry Fritz "
>Hi all
>I am using a 9kv at 120ma NST. In operation I use an iron vane ammeter
>(known to be within 5% accuracy) to monitor current. My mains voltage is
>nominally 117V. Interestingly the current into the NST is about 17A when
>running in resonant mode. It is my understanding that an iron vane meter
>reads true input current regardless of waveform. Therefore my input power to
>the NST is nearly 2000 watts.
>I would appreciate comments from anyone who can help explain the discrepancy
>between the 1080va rating of the "current limited NST and the measured input
>in resonant mode operation.
>Skip
>
>
>
>-Chris
>