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
>
> _______________________________________________
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> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
--
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/
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