Alpha and others have been using toroids for 4 decades in L networks at
1500-2500W with no problems.
The material used is a 2 Mix powdered iron from Micrometals with the cores
appearing to be a stacked pair of T-225A's.
Preparation is important and they are each wrapped with HV tape such as
Scotch 27, stacked and wrapped again. Wire is Teflon insulated and mounting
is with nylon or fiberglass hardware.
Carl
KM1H
----- Original Message -----
From: "Karl-Arne Markström" <sm0aom@telia.com>
To: "Ulf Tjerneld" <star@frizon.org>; <Amps@contesting.com>
Sent: Wednesday, January 06, 2010 2:16 PM
Subject: Re: [Amps] L section of Pi-L filter
> 1. Toroids have to be quite heavily dimensioned, as
> they are storing a lot of magnetic energy in a small space.
> At an L-network Q of 2 they have to store at least 2000 VAr in the toroid
> magnetic material, and the corresponding flux density is quite high.
>
> Even the largest iron-power toroids available may be marginal in this
> application, as the core losses for i.a. #2 material are in the 10's of
> watts range.
>
> 2. Using "reasonable" network Q:s, the current in the L-network part is
> about 80 - 90% of the current flowing in the Pi-part, so the same wire
> gauges are required.
>
> The "Pi-L Designer" utility by Jim Tonne is a very useful tool for output
> circuit design, together with the DL5SWB Mini Ring Core calculator.
>
> 73/
>
> Karl-Arne
> SM0AOM
>
>
> ----- Original Message -----
> From: "Ulf Tjerneld" <star@frizon.org>
> To: <Amps@contesting.com>
> Sent: Wednesday, January 06, 2010 7:33 PM
> Subject: [Amps] L section of Pi-L filter
>
>
>> Hi,
>>
>> Question 1: I'm considering using toroids in the L-section of my RF tank.
>> Are there any guidelines regarding suitable cores, wires and turns?
>>
>> Question 2: If I stay with a traditional air wound coil for the L-section
>> what would be a suitable wire diameter for a 1 KW amp? I'm pretty sure it
>> does not have to be the same heavy gauge as in the Pi-section!
>>
>> Thanks for any answer!
>>
>> 73's Ulf /SM0NOR
>> _______________________________________________
>> Amps mailing list
>> Amps@contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>
>
> --------------------------------------------------------------------------------
>
>
>
> No virus found in this incoming message.
> Checked by AVG - www.avg.com
> Version: 9.0.725 / Virus Database: 270.14.127/2603 - Release Date:
> 01/06/10
> 08:35:00
>
> _______________________________________________
> 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
|