[Boatanchors] PLATE XFMR

[J. Forster]

The 40 W/lb is a design number we used in the early-mid '70s for common
garden silicon steel E-I laminations.

-John

===============



> There have been several different grades of transformer iron made since
> the
> 20's with each new one being more efficient.
>
> You can trust the ARRL to be a step behind.
>
> Ive used the dummy load method many times to monitor temperature rise when
> an open frame xfmr makes it easy. OTOH, those cast iron end bells take
> ages
> to absorb the heat and the windings could be toast by the time you realize
> it. And you never know what is inside a sealed unit.
>
> The problem with old design high impedance windings is that a choke input
> is
> necessary to get any reasonable regulation under changing loads. You could
> do it with a lot of C only but that requires a lot of wasted bleeder
> current. Best keep the old iron with Class C amps and modulators.
>
> Carl
> KM1H
>
>
>
> ----- Original Message -----
> From: "J. Forster" <jfor at quik.com>
> To: "Bill and Liz McHugh" <magoo at isp.ca>
> Cc: <boatanchors at mailman.qth.net>
> Sent: Monday, April 04, 2011 1:57 PM
> Subject: Re: [Boatanchors] PLATE XFMR
>
>
>> Roughly 40 watts/pount at 60 Hz for a transformer made with standard
>> (cheap) iron.
>>
>> -John
>>
>> ===============
>>
>>
>>
>>> Some time ago I recall someone providing a "rule of thumb" one might
>>> use
>>> to estimate the current capacity of a plate transformer based on weight
>>> and dimensions.
>>>
>>> I have a Hammond with an REL number which is not in any catalog and
>>> would
>>> like to be able to use it in a supply for an 813 rig I am building.
>>>
>>> Anyone have that "rule of thumb" at hand?
>>>
>>> Bill VE3NH
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>>
>>
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>>
>>
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>
>