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Re: MOT testing

Original poster: "Alexander Rice by way of Terry Fritz <twftesla-at-qwest-dot-net>" <alex-at-rices.myip-dot-org>

27/05/2002 05:47:31, "Tesla list" 
<tesla-at-pupman-dot-com> wrote:

>Original poster: "Dale Nassar by way of 
Terry Fritz <twftesla-at-qwest-dot-net>" 
>Why are you increasing the wattage--Is it 
for voltage reasons--It cant be 
>because a 15/30 NST is overheating a 100W 
1kOhm resistor.  I have tested 
>15/30 NST's with a TINY 1/4 watt 
> From standard formulas:
>30mA -at- 1000 Ohms (I*I*R) dissipates only 
0.9 watt--a watt 1 resistor holds 
>a 15/60 NST imposes 3.6 Watts.
>Looks like you need to go DOWN to 5W  >>
not UP to 200W<<
>--dale nassar

	this holds true for current limited 
transformers like NST's but MOT's are 
current limited to a much higher current - 
they can deliver about 700ma at 2500v or 
so. since I=v/r  I=2500/1000 = 25A!, so 
the resistor os a good as a dead short. 
this menas the full 700-1000 ma will flow 
which means a power dissipation of 490w to 



ps: the best way to measure the current 
would probably be to use a conventional 
ammeter with around 0.1 ohms internal 
resistance - just make sure it isnt 
digital 1^2 * 0.1 (worst case) is still 
only 0.1 watts
Alexander JJ Rice
Rank : G-2 (Wahey!)
"Because the Geek Shall Inherit the Earth