Nondestructive transformer tests?
« on: March 16, 2015, 06:35:58 PM »
Hello,
What are the best ways to non-destructively get information on audio transformers? I've fished a 10 turn winding around the core, as RG Keen recommends to find the turn counts. Promising results there.

The biggest problem I'm having is getting a consistent measurement of inductance. Just touching a coil for several seconds sways the measurement a large amount. Is there a formula to measure the core temp and standardize inductance measurements made at various temps? Resistance varies too, but not as much.


mjrippe

Re: Nondestructive transformer tests?
« Reply #1 on: March 16, 2015, 06:45:51 PM »
Are you using pointed probes or alligator clips?  Clips will give you more consistent contact with the wires while probes sometimes drift - especially if you are using your fingers to hold them to the wires  ;D

EmRR

Re: Nondestructive transformer tests?
« Reply #2 on: March 16, 2015, 08:35:20 PM »
CJ (somewhere in his 10K posts) has addressed how small amounts of pressure on a core will affect L readings.   Basic L readings are at best a suggestion, further testing required.   I can measure during different seasons at different temps and get different results.
Best,

Doug Williams
Electromagnetic Radiation Recorders

"I think this can be better. Some kind of control that's intuitive, not complicated like a single knob" - Crusty

"Back when everything sounde

Re: Nondestructive transformer tests?
« Reply #3 on: March 17, 2015, 10:14:44 PM »
Thanks fellas! I am using alligator clips on short leads.

I've searched through CJ's  post history dozens of times for various reasons, will give it another round on this topic.