[Boatanchors] Large 4.25 Henry Choke

J. Forster jfor at quik.com
Mon Feb 28 18:49:07 EST 2011


> Guys - the bottom line is this thing will certainly handle a ham gallon
> power supply as part of a choke input filter or as a PI network filter
> and I don't believe it will get hot or disipate 800 watts in such an
> application as some here claim,

If you put 4.25 A through a 39 Ohm resistor, it IT WILL DISSIPATE about 
800 W. Ohms law is true.

 - not unless you short out your
> RF final tubes to ground anyway! It's not going to get very hot in
> amateur AM, SSB or CW service!
>
> The perfectionist dissection has run its course. Time for the empirical
> radio amateurs to have their go at this now.... grin!

Perfectionist??  You mean day 1 of Elementary Electronics 101??

-John

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


>
> I tested the choke and it is good, so whoever wants it can play with
> it happily.
>
> --------------------------------------------------
> On 28 Feb 2011 at 18:16, Bry Carling wrote:
>
> The label is a little hard to read. At first glance it looked like 445
> amps,
> but I knew that wasn't rght. I just couldn't spot a DOT - "."
> anywhere on the faded label.
>
> Now, I think I might see a faint "1" ahead of the 445A which would
> make more sense... That is to say 1.445 Amps... Seem reasonable?
> What a funny rating for them to use and be so specific. But then, it is
> G.E.
> (grin!)
>
> Bry, AF4K
>
>
> On 28 Feb 2011 at 16:00, George Babits wrote:
>
>> At the risk of receiving some scathing comments I have to say that
>> the
>> purpose of a power supply choke is to smooth rectified DC, not
>> generate or
>> dissipate power. Judging from the size of this choke it is probably
>> .45
>> amps. The resistance is the DC resistance so you have some idea of
>> what the
>> voltage drop across the choke will be when you design your power
>> supply.
>> 73,
>> George
>> W7HDL
>>
>>
>> ----- Original Message -----
>> From: "Lewis C. Emerson" <lemerson at juno.com>
>> To: <jfor at quik.com>
>> Cc: <boatanchors at puck.nether.net>; <armyradios at yahoogroups.com>
>> Sent: Monday, February 28, 2011 3:51 PM
>> Subject: Re: [Boatanchors] FS: Large 4.25 Henry Choke
>>
>>
>> > John - If its 0.45 A doesn't that mean it's an 8 watt unit?
>> Mighty big
>> > for just 8 watts. Must be lotsa iron in there. - Doc, W4ITJ
>> >
>> > ---------- Original Message ----------
>> > From: "J. Forster" <jfor at quik.com>
>> > To: bcarling at cfl.rr.com
>> > Cc: boatanchors at puck.nether.net, armyradios at yahoogroups.com
>> > Subject: Re: [Boatanchors] FS: Large 4.25 Henry Choke
>> > Date: Mon, 28 Feb 2011 12:10:15 -0800 (PST)
>> >
>> > I don't think so.
>> >
>> > Power = I^2 * R
>> >
>> > = 4.45 ^2 * 39 = 800 W
>> >
>> > Maybe, 0.45 A
>> >
>> > -John
>> >
>> > =====================
>> >
>> >
>> >> FOR SALE: General Electric ChokeType 7471984
>> >>
>> >> 4.25 H at 39 ohms resistance. Current rating appears to read
>> >> 4.45A but not sure. Made in Schenectady, NY
>> >> Dimensions: 5" X 3-5/8" X 4-3/8" tall.
>> >> Painted gray, potted, and as ceramic screw terminals with brass
>> >> nuts on the top of one end.
>> >> Mounts via four screw #10 holes in base.
>> >>
>> >> QTY 1 available for $15.00 plus shipping.
>> >>
>> >> 73 de AF4K, Bry Carling
>> >> _______________________________________________




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