Hi Jim, Thanks for that, It seems that these could well be useful. they
certainly work well tuning my receive solenoid. You certainly get a good
sized lump or ferrite for your £3-00
Cheers de Alan G3NYK
alan.melia(at)btinternet.com
----- Original Message -----
From: "James Moritz" <[email protected]>
To: <[email protected]>
Sent: 26 September 2004 23:45
Subject: LF: Re: fluted ferrite cores
Dear Alan, LF Group,
The fluted ferrite rods are probably "impeder rods" - these are used for
induction welding of the seams in metal tubing produced by rolling strip
metal. They fit inside the tube at the point where the weld is being made.
Their purpose is to force the induced current to flow through the weld,
rather than around the circumference of the tube; there is a fairly good
description at:
http://www.impeder.com/Efficiency/efficiency.html
The purose of the flutes is to allow the circulation of cooling water,
allthough it may also be significant in reducing eddy currents. My old
Philips ferrite data book lists these as available in either 3C85 or 3D3 (a
somewhat lower permeability ferrite otherwise similar to 3C85). The
induction welding application normally operates in the LF/MF range at the
10s of kW level - potentially these might be useful in an LF TX loading coil
application, if a coil using them can be made with high enough Q...
Cheers, Jim Moritz
73 de M0BMU
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