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## Re: [Amps] reducing the reactance of a wirewound resistor

 To: Vic K2VCO , "amps@contesting.com" Re: [Amps] reducing the reactance of a wirewound resistor "Fuqua, Bill L" Mon, 6 Feb 2012 02:06:58 -0500 mailto:amps@contesting.com>
 ```check out these resistors. http://token.com.tw/resistor/wirewound-resistor2.htm also click on the General Specifications tab and you will find a picture of the counter wound wires. 73 Bill wa4lav ________________________________________ From: amps-bounces@contesting.com [amps-bounces@contesting.com] On Behalf Of Vic K2VCO [k2vco.vic@gmail.com] Sent: Sunday, February 05, 2012 7:01 PM To: amps@contesting.com Subject: Re: [Amps] reducing the reactance of a wirewound resistor What HB9SLV suggested was not exactly an Aryton-Perry winding, although the principle is the same. Instead of being in parallel, his idea had the windings in series. So they will always carry the same current! On 2/5/2012 9:23 AM, jeff millar wrote: > Interesting... I looked up Aryton-Perry winding as a result. The Wikipedia > entry pointed out ... > > "One disadvantage is that because the two lengths of resistive wire are > connected in parallel, four times the length of wire (twice the length for > each coil) is needed to make a given resistance than if a single coil was > used." > > That led to the realization that the two windings have to carry the same > current > to have the magnetic fields cancel...which means they have to have the same > resistance. > > Conclusions... > - start with 100 Ohm wire wound resistor > - count the turns > - wind 100 Ohms worth of copper over the same length > - for same turn count, need smaller diameter wire > > jeff, wa1hco > > On 02/03/2012 03:23 AM, Angel Vilaseca wrote: >> Hi all >> >> I have a nice large 50 ohms wirewound resistor, which I would like to >> use as a dummy load. Problem is, it is inductive of course. >> >> To cancel the inductive reactance I was thinking of winding some >> enameled wire all along over the resistor, with as many turns as the >> resistive wire, solder the enameled wire to the resistor terminal at one >> end and feed the RF at the other two separate terminals (wire and >> resistor) at the other end. >> >> The idea is that the inductive reactance of the resistor winding and the >> enameled wire winding will cancel each other. With some care and >> measuring gear the remaining reactance could be very low. The assembly >> would then behave almost as a pure resistance. >> >> Of course, care should be taken not to reach too high temperatures, >> because the enameled wire would then be damaged. >> >> Also, the added winding should be wound in the appropriate diraction ( >> CW or CCW depending of the winding direction of the resistive wire) >> otherwise the two inductances would add instead ao canceling each other. >> >> Has anyone alredy tried this? >> >> 73 >> >> Angel Vilaseca HB9SLV >> _______________________________________________ >> Amps mailing list >> Amps@contesting.com >> http://lists.contesting.com/mailman/listinfo/amps > > _______________________________________________ > Amps mailing list > Amps@contesting.com > http://lists.contesting.com/mailman/listinfo/amps -- Vic, K2VCO Fresno CA http://www.qsl.net/k2vco/ _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps ```
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