Hey Jay...having the wiper somewhat in the middle of the windings seems to reduce the initial magnetic flux thru the core of the variac. Depending on how you have the Variac wired for output, it can be a healthy inital surge. If wired for say line voltage in and line voltage out at max rating, the surge is almost minimal when starting( turning on) the variac at full voltage since the wiper is at the end of the windings with little magnetic field flux being produced. If you have it wired for 120 in and 140 out at max settings, there is going to be the inital magnetic flux incurred to give you the 140 V out.
The unit is rated for 22.5 amps current capacity, in other words it will handle a current of 22.5 amps max thru it to the load it is supplying. If you were to put a load on the variac that can draw more than 23 amps, the Variac will overheat and smoke and eventually die... most of the times, variac failure occurs where the wiper ( brush) is in contact with the windings, either the brush arcs out or the windings melt and break.
Just wondering.... how do you have the variac wired up???? Did it come with a prewired wall plug attached, or did you have to put one on yourself? What brand is the Variac??
Scot D jhowson4@xxxxxxxxxxx wrote:
Ok this is attempt 3 my e-mail keeps saying that there was a sending error. so if 3 of the same message were in fact sent i am sorry. Ok so i think that this so called surge is the culprit since at the time of the breaker being blown I was trying to figure out where a weird sound was coming from and this entailed turing it on and off. learing from my mistakes i won't be doing that again... ever... How much current is the norm if nothing is plugged into it? If the unit is rated for 22.5 amps why is it not pulling that much power all the time? How does starting the variac with it turned up help. I understand what you want me to do but I am curious as to why it works. Even if the surge current was the culprit i want to be sure before I plug it back in and the people start asking why stuff blew.Thanks, Jay. H_______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla
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