[Boatanchors] is it a Choke or a Filter Reactor?

[rkerr]

A swinging choke usually has an air gap somewhere in the circuit of the 
magnetic core material.  If you have an open frame swinging choke you 
can usually find the gap around the perimeter of the core.  For 
instance, if the core is an iron bar (or a stack of plates) shaped like 
a rectangle, somewhere there will be a thin break in the rectangular 
circuit.  The air gap limits the intensity of the magnetic flux that can 
be generated in the iron core.  The effect this has on the choke is that 
the inductance for low currents, where the core magnetic flux limit has 
not been reached, is much higher than the inductance for high currents 
where the core flux is saturated. 

Swinging chokes are usually used in power supplys that need a high 
peak-to-average current output capability.  For low or average currents, 
the choke will have high inductance and act as a good filter (for AC 
hum, for instance), while at the same time the choke inductance will 
decrease for high currents so as not to cause a high series voltage drop 
when a peak current pulse occurs.  AM and SSB transmitters have this 
type of current characteristic.

Vincent Del Toro is a prolific writer of textbooks on transformers and 
electric machinery.  Most basic textbooks on electric motors begin with 
a chapter or two on inductors and transformers.  You might find used 
copies on Amazon.

Bob
WB4TGG


ELDIM wrote:

>Hello All,
>With all that said, "Is there a sinple test to tell you how to distinguish
>between a normal power supply choke vs a Swinging choke"?   I am under the
>understanding that a swinging choke, has more fun, is wound differently than
>a nomal reactor. The reactance varies according to the current flowing
>through the inductor. Hope to hear from some real techno wizards.  Also, is
>there any reference reading on the subject.
>
>73,
>Glen Galati, KA7BOJ
>Tacoma, WA eldim at att.net
>
>----- Original Message -----
>From: "George KB2Z" <Thermionic_Emission at earthlink.net>
>To: "rkerr" <rrkrr at mindspring.com>; "boatanchors-mailman.qth.net"
><boatanchors at mailman.qth.net>
>Sent: Friday, October 29, 2004 6:14 AM
>Subject: Re: [Boatanchors] is it a Choke or a Filter Reactor?
>
>
>  
>
>>In the "Illustrated Dictionary of Electronics" under filter reactor, and
>>filter inductor it says, See filter choke.
>>
>>At 08:28 AM 10/29/04 -0400, you wrote:
>>
>>    
>>
>>>Greg,
>>>"Reactor" refers to the inductor's positive reactive AC circuit
>>>impedance.  "Choke" whether for a DC power supply filter or for higher
>>>frequencies ("RF choke") refers to the blocking effect of the inductor
>>>      
>>>
>for
>  
>
>>>higher frequencies, that is, DC currents are passed with little loss,
>>>while higher frequencies are diminished or "choked" off.   That said, I
>>>don't know of any industry standard technical distinction between the
>>>terms "Filter Choke" and "Filter Reactor" when referring to big, heavy,
>>>iron core inductors used in DC power supply filter circuits.  I believe
>>>these are just two interchangeable terms used to refer to the same thing.
>>>
>>>Bob
>>>WB4TGG
>>>
>>>Greg Mijal wrote:
>>>
>>>      
>>>
>>>>Is there a substantial  difference between the terms: Choke and Filter
>>>>Reactor?
>>>>I have a Thordarson T20C57 10h @ 500 ma monster stamped "Filter Reactor"
>>>>So why not mark it "Choke" ?
>>>>Could "Filter Reactor" be a bygone term for swinging choke?
>>>>Thanks
>>>>Greg
>>>>WA7LYO
>>>>in rainy feenix
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>>>      
>>>
>
>
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>----
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>>
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>>    
>>
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