Re: PTs

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

Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" <Tesla729-at-cs-dot-com>

In a message dated 4/14/01 9:29:19 PM Central Daylight Time, tesla-at-pupman-dot-com 
writes: 

Christopher Boden wrote: 

>
> That's what I though, but what if it's just a matter of a REALLY low primary 
> resistance? Couldn't that appear to the breaker as a short? 
>



Hi Chris, 

If it were a case of very low initial inductive reactance at the first 
application of power, then the breaker would trip immediately up- 
on application of power, not wait a couple of seconds and then trip. 
Also, this situation usually occurs intermittently, not every time that 
power is applied. If power is applied at just the right time of the 
60 hz sine wave input, the mains power supply may see the inductive 
load as a momentary short, before the inductive reactance has a 
chance to kick in its current limiting mode, but obviously this wouldn't 
occur every time that power was applied since you're not going to al- 
ways turn on the power at the same point of the mains 60 hz sine wave. 

<Yup, but, even if it's got a HV side short, it's a beautiful bit of 
<inductive ballast :) 

Yep, you've got a point there. 

David Rieben