Anyone measured Edcor trafos primary inductance?

I'm messing around with transformers here, and purchased an LCR meter.
So I wound a small transformer and got 60H at the primary.
I measured the famous UTC A-24 and got whopping 1500H (both primaries in series, at 100Hz)
Now, I wonder what Edcor's primary inductance is like, the 10k:600 ones...

We have discussed this a while back. If you make any new measurments please let me know and I will add them to the document.

http://www.groupdiy.com/index.php?topic=47515.msg597880#msg597880

Cheers

Ian

Hey Ian, thanks!
I will measure a number of transformers and PM you the results!
Cool thread you linked, how did I miss that!
8)

jackies said:

I'm messing around with transformers here, and purchased an LCR meter.
So I wound a small transformer and got 60H at the primary.
I measured the famous UTC A-24 and got whopping 1500H (both primaries in series, at 100Hz)
Now, I wonder what Edcor's primary inductance is like, the 10k:600 ones...

Click to expand...

UTC A24 is rated at 15k primary impedance, which suggests a minimum of 120H@20Hz, but since it is used with DC current, it has to be designed for a much higher value.

I thought the A-25 was the model rated for DC...??

JC

rascalseven said:

I thought the A-25 was the model rated for DC...??

JC

Click to expand...

rated for unbalanced DC.  A-24/26 used for PP balanced DC vs cap coupled, which is generally what most Edcors will be used for.



On one Edcor WSM 15K:600 I measured 46.3H @ 120Hz

So think in terms of using it in cap coupled output stage,  5-7K source impedance which will fall even lower with negative feedback.

rascalseven said:

I thought the A-25 was the model rated for DC...??

JC

Click to expand...

You're  absolutely right; my mistake.
So 1500H suggests ca. 2Hz LF response !...?

CJ did a post-mortem of the A24, giving different (and more likely) results.
http://www.groupdiy.com/index.php?topic=35712.0

abbey road d enfer said:

CJ did a post-mortem of the A24, giving different (and more likely) results.
http://www.groupdiy.com/index.php?topic=35712.0

Click to expand...

Well, CJ doesn't state the measuring frequency - if it was somewhat higher than 100hz, the measured inductance would be lower.
Then, series connection of the windings doesn't double the inductance, it's more like square of turns or something?
So I don't think 119H for one winding (at possibly higher frequency) is that much different from 1500H for two windings in series (at 100Hz)
:
I will measure the windings separately as well, to see how that applies.
Whenever I get around to that...
;D