[Test-Equipment] Rewind a transformer!

[Mike Manes]

He mentioned coming up with a volts-per-turn figure in order
to determine the number of secondary turns, but if he muttered
how he did that, I missed it.  The way I do it is to wind a
known number turns on the core, fire it up and measure the
secondary voltage.  10-20 turns will probably do for a mains
freq xformer, and only 1 or 2 on a HF device.

What I found neat was his layering tool.  I do that with great
tedium manually, and an occasional unwind if I mode too fast or
slow.

73 de Mike W5VSI

On 2/13/13 6:13 PM, Randy D. Hunt wrote:
> On 2/13/2013 1:08 PM, David wrote:
>> On Wed, 13 Feb 2013 10:14:40 -0800, "Randy D. Hunt"
>> <randy_hunt960 at yahoo.com> wrote:
>>
>>> On 2/12/2013 11:12 PM, Dave C wrote:
>>>> http://www.youtube.com/watch?v=ZVSbt5q0KF8
>>>>
>>>> Very creative...
>>>>
>>>> Dave
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>>> I like the idea of the transformer kit.  Did anyone notice the
>>> difference in the amount of iron in the core as compared to the stock
>>> transformer.  I would say the kit has about 2/3rds of the iron.  This
>>> could be making his transformer run hot thereby causing him to have to
>>> rewind it. . .  Just a thought.
>>>
>>> Randy, KI6WAS
>> Presumably he adjusted the number of primary and secondary turns while
>> keeping their ratio constant to achieve the recommended magnetic flux
>> density at 50 Hz if the cross sectional area was different.
>>
>> Only two of the windings were moved to the transformer.  He kept the
>> old one with those two windings removed and placed the primaries of
>> both transformers  in parallel.
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> Oh, yes, 50Hz.  I forgot about the lower line frequency. . .
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