Please forgive me if this is not the appropriate location for this question.

I have a transformer (a nice chunky one). It seems to test o.k. Logically it looks in good condition. It has no labeling on on it. (if there is a tutorial on figuring this out, please point me in that direction and don't read on).

I'm trying to figure out the winding ratio's. I'm doing the following.

1 - AC10v in on the various windings, and measuring the voltages on the output (with an oscilloscope).
2 - Measure the resistance (as best I can) to compare the ratios.
3 - Measuring the inductance between the winding to also compare the winding ratios'.

My question is... Why o why is there such a HUGE difference in my ratio's between the measurements. resistance I can understand... I would have though there would have been a close resemblance between a voltage and inductance test. but I'm out by about %50 between the tests (a repeat of the same tests give the same results. I realize I could increase my voltage input to increase my accuracy (24 volts would be an interesting low voltage to try, I'm sure all would become really clear)... but fancy me not wanting to do this for a play exercise. BTW I'm not discounting the possibility of this being faulty in some way, but I'd be surprised.

I'm not short of parts and I don't mind recycling this, but at this point it's a skill building exercise and I'm interested.

This is me asking help from someone out there with 'black belt' knowledge. In my mind, these methods should "workish".

Thanks in advance!

 

The voltage ratio of a transformer is the ratio of the number of turns in each winding, however the inductance of a coil is proportional to the square of the number of turns. So with a 1:2 transformer you would expect the secondary to have four times the inductance of the primary.

 

Cool,

Thanks for removing my 'am I on drugs?'... I'm not going to spend another second on this.
Just fyi, I dusted of an old transformer (old project) did the same test and got much nicer results.