[Johnson] Need tech advice on xfmr

[David C. Hallam]

Ed,

Unless some of the transformer guys weigh in and show me that I am wrong, I
will stick by my contention that the transformer is rated for approximately
25 watts in CONTINUOUS duty service with the center tap grounded.  I will
agree that for intermittent duty service with a light bleeder load, you can
get for than 25 watts out of it.  Leaving the center tap above ground does
not increase the power rating of a transformer.

-----Original Message-----
From: Ed Tanton [mailto:n4xy at earthlink.net]
Sent: Saturday, November 26, 2005 9:52 PM
To: dhallam at rapidsys.com; C E; johnson at mailman.qth.net
Subject: RE: [Johnson] Need tech advice on xfmr


Not correct: IF the transformer is indeed rated for 520VAC at 90mA,
then (regardless of the CT) it is capable of ~ 46W. Period.

At 01:24 PM 2005-11-26, David C. Hallam wrote:
>The answer is maybe.
>
>The transformer rating is approximately 520/2 x .090 = 23.4 watts.
>Depending upon the size of wire used to wind the transformer you could
>probably get 120 mA at 260 VDC out of it.  Breadboard the rectifier circuit
>and let it run for awhile and see how hot the transformer gets.  If it gets
>too hot to touch, the answer is no it won't work.
>
>No, it is not rated for 180 mA in a FWB.
>
>73
>David
>KC2JD
>
>-----Original Message-----
>From: johnson-bounces at mailman.qth.net
>[mailto:johnson-bounces at mailman.qth.net]On Behalf Of C E
>Sent: Saturday, November 26, 2005 1:05 PM
>To: johnson at mailman.qth.net
>Subject: [Johnson] Need tech advice on xfmr
>
>
>Speaking of xfmrs, I would like to know (say, a
>replacement xfmr for an EFJ transmitter) is rated at
>520 VCT at 90 mA and I would like to use it in another
>application that requires 260 VDC at 120 mA, would
>this transformer work without getting fried? Does the
>90 mA mean 180 mA in full bridge configuration?
>Thanks. Cal.
>
>
>
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Ed Tanton

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