Received-SPF: neutral (google.com: 195.171.43.25 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) client-ip=195.171.43.25;
Message-ID: <5220A31C.5080406@iup.uni-heidelberg.de>
Date: Fri, 30 Aug 2013 15:50:20 +0200
From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= <Stefan.Schaefer@iup.uni-heidelberg.de>
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3
MIME-Version: 1.0
To: rsgb_lf_group@blacksheep.org
References: <7E7DFBB4D102A04DB5ADC88D66628A4A0FC368A8@ICTS-S-MBX1.luna.kuleuven.be>
In-Reply-To: <7E7DFBB4D102A04DB5ADC88D66628A4A0FC368A8@ICTS-S-MBX1.luna.kuleuven.be>
Subject: Re: LF: iron powder toroid cores
Content-Type: multipart/alternative;
 boundary="------------020302000102010207010006"
Sender: owner-rsgb_lf_group@blacksheep.org
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org
Status: O

This is a multi-part message in MIME format.
--------------020302000102010207010006
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit

Hello Rik,

A T200-2 will have no problem with 500W on 475 kHz! Belive me :-)

73, Stefan/DK7FC

Am 30.08.2013 09:30, schrieb Rik Strobbe:
>
> Dear all,
>
> I intend to replace the air coils in the LPF on my 475 
> kHz transmitter by toroid core coils. I have a stock 
> of T200-2 cores but for the power level want to get 
> (500W would be required to get near the 5 W EIRP limit)  one T200-2 
> is just on the edge in regard with the maximum flux 
> (and thus temperature rise.
>
> To be on the save side I would use 2 T200-2 toroids for each coil, 
> and there are 2 options:
>
> 1. Glue 2 cores together to make one core of the double height.
>
> This would reduce the flux to 70%, well under the 
> limit. It would also reduce the number of windings to 70%, but due to 
> the double coil height the wire length will increase slightly (abt. 10%).
>
> But as the cores have rounded egdes there wil be some 
> air space between the wire an the core, what might increase loss.
>
> 2. Put 2 toroid core coils, each of half the inductance, in series.
>
> This will also reduce the flux to 70%, but 
> the total wire length needed will increase by abt. 40%.
>
> In option 1 I will need lees wire (= less loss) compared to option 
> 1, but the air space might undo this advantage.
>
> So my question is: what will be best?
>
> All advice is welcome.
>
> 73, Rik  ON7YD - OR7T
>

--------------020302000102010207010006
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
  <meta content="text/html; charset=ISO-8859-1"
 http-equiv="Content-Type">
</head>
<body bgcolor="#ffffff" text="#000000">
Hello Rik, <br>
<br>
A T200-2 will have no problem with 500W on 475 kHz! Belive me :-)<br>
<br>
73, Stefan/DK7FC<br>
<br>
Am 30.08.2013 09:30, schrieb Rik Strobbe:
<blockquote
 cite="mid:7E7DFBB4D102A04DB5ADC88D66628A4A0FC368A8@ICTS-S-MBX1.luna.kuleuven.be"
 type="cite">
  <meta http-equiv="Content-Type"
 content="text/html; charset=ISO-8859-1">
  <style id="owaParaStyle">P {
	MARGIN-TOP: 0px; MARGIN-BOTTOM: 0px
}
  </style>
  <div
 style="direction: ltr; font-family: Tahoma; color: rgb(0, 0, 0); font-size: 10pt;">
  <p>Dear&nbsp;all,</p>
  <p>&nbsp;</p>
  <p>I&nbsp;intend to&nbsp;replace the air&nbsp;coils in the LPF&nbsp;on&nbsp;my 475
kHz&nbsp;transmitter&nbsp;by&nbsp;toroid core coils. I have a stock of&nbsp;T200-2&nbsp;cores&nbsp;but&nbsp;for
the power level&nbsp;want to&nbsp;get (500W&nbsp;would&nbsp;be&nbsp;required to&nbsp;get&nbsp;near the 5
W&nbsp;EIRP limit)&nbsp;&nbsp;one&nbsp;T200-2 is&nbsp;just&nbsp;on the&nbsp;edge in&nbsp;regard&nbsp;with the
maximum flux (and&nbsp;thus&nbsp;temperature rise.
  </p>
  <p>To&nbsp;be&nbsp;on the save&nbsp;side I&nbsp;would&nbsp;use 2&nbsp;T200-2&nbsp;toroids&nbsp;for&nbsp;each coil,
and&nbsp;there are 2 options:</p>
  <p>&nbsp;</p>
  <p>1.&nbsp;Glue 2&nbsp;cores&nbsp;together to&nbsp;make&nbsp;one core of the double height.</p>
  <p>This&nbsp;would&nbsp;reduce the flux to 70%,&nbsp;well&nbsp;under the limit.&nbsp;It&nbsp;would&nbsp;also&nbsp;reduce
the&nbsp;number of&nbsp;windings to 70%,&nbsp;but&nbsp;due to the double&nbsp;coil&nbsp;height
the&nbsp;wire&nbsp;length&nbsp;will&nbsp;increase&nbsp;slightly (abt. 10%).</p>
  <p>But&nbsp;as the&nbsp;cores have&nbsp;rounded&nbsp;egdes&nbsp;there wil&nbsp;be&nbsp;some air&nbsp;space&nbsp;between
the&nbsp;wire&nbsp;an the core,&nbsp;what&nbsp;might&nbsp;increase loss.</p>
  <p>&nbsp;</p>
  <p>2. Put 2&nbsp;toroid core coils,&nbsp;each of half the inductance, in series.</p>
  <p>This&nbsp;will&nbsp;also&nbsp;reduce the flux to 70%,&nbsp;but the&nbsp;total&nbsp;wire&nbsp;length&nbsp;needed&nbsp;will&nbsp;increase&nbsp;by
abt. 40%.</p>
  <p>&nbsp;</p>
  <p>In&nbsp;option 1&nbsp;I&nbsp;will&nbsp;need&nbsp;lees&nbsp;wire (=&nbsp;less loss)&nbsp;compared to&nbsp;option
1,&nbsp;but the air&nbsp;space&nbsp;might&nbsp;undo&nbsp;this advantage.</p>
  <p>&nbsp;</p>
  <p>So&nbsp;my&nbsp;question is:&nbsp;what&nbsp;will&nbsp;be best?</p>
  <p>All&nbsp;advice is welcome.</p>
  <p>&nbsp;</p>
  <p>73, Rik&nbsp;&nbsp;ON7YD - OR7T</p>
  <p>&nbsp;</p>
  </div>
</blockquote>
</body>
</html>

--------------020302000102010207010006--