Filament winding -- finding the Amp rating when unknown

[Phil_S]

It seems too good to be true. Is it this simple?

I've got a big wirewound 15 ohm pot (meant for use in an attenuator, not sure of wattage, but it's big). If I hook the 6.3v winding to the pot, and turn the dial until I hit 6.3vac output on the DMM, then read the ohms on the pot, I can calc for I as in V/R=I? In other words, if output is 6.3vac and the pot is set for 3 ohms, then the winding is rated at 2.1A?

This seems like a "no smoke" test, as in a rather reduced possibility of letting the smoke out of the tranny. Might possibly smoke the pot (not much buzz potential, I guess), in which case, I can shut it down before the PT starts to smoke.

Like I said, this seems too good to be true.

Advice please?

[VacuumVoodoo]

Yes, it's that simple for general check-up.

[Phil_S]

How cool! Thanks for the confirmation. I was just a bit uneasy that anything could be so simple. I understand that transformers are more complex that that. I'm just trying to find a sensible limit. I don't expect to find the upper limit, since the only way to do that is to actually smoke the transformer. We all know, once you let the smoke out, you can only put it back with a pile of money that is bigger than the cost of a new one.

I would be very happy to find 2.1A on the 6.3v and 2.0A on the 5V. These are numbers that "work".

[jjman]

Just make sure you start from the 15ohm position and not the 0ohm postition.

[Wayne]

Another tip - do all your testing while your head is clear, then "smoke the pot" once you're finished

W

[gahult]

Any 3 ohm load you put on there will draw 2.1A whether the winding is rated for that or not. If it isn't expect smoke, overheating or any kind of surprise. If it doesn't overheat you can I suppose figure it's rated to take that load.

Gary