[Boatanchors] [Milsurplus] 12-24 vdc converters and toroid cores

[Al Klase]

Hey Mike,

Let us know how that thing works.  I've been tempted to get one of 
those.  It looks like a much better solution to the 24-volt radio in a 
12-volt vehicle problem.  All this change the alternator/use two 
batteries stuff is fraught with complications.

I've also contemplated building an inverter, but as the original poster 
pointed out, the magnetics (the transformer core) are a major question 
mark.  If there's a good $100 solution, it's not worth the engineering 
exercise.

Al

Mike Feher wrote:
> I admit that I have not been following thread, so, please take my comments
> accordingly - About a week or so ago I purchased a 12 to 24 volt converter
> from a guy in Israel on eBay. It arrived in good shape, and with connectors.
> I believe this was intended for the RT-524, and, with shipping it was just a
> little over $100. Have not tried it yet. He seems to have several. 73 - Mike
>
> Mike B. Feher, N4FS
> 89 Arnold Blvd.
> Howell, NJ, 07731
> 732-886-5960
>
>   
>
> -----Original Message-----
> From: milsurplus-bounces at mailman.qth.net
> [mailto:milsurplus-bounces at mailman.qth.net] On Behalf Of Peter Gottlieb
> Sent: Monday, October 05, 2009 7:17 PM
> To: Michael Tauson
> Cc: boatanchors at mailman.qth.net; milsurplus at mailman.qth.net;
> boatanchors at lists.tempe.gov
> Subject: Re: [Milsurplus] 12-24 vdc converters and toroid cores
>
> Simplified:  the current times time during the magnetizing part of the 
> waveform must not saturate the core.  Raising the frequency reduces 
> that, but core losses can increase depending on core material.
>
> You can monitor the primary current to watch for saturation by using 
> either a current probe or a series small value non-inductive resistor.
>
> Peter
>
>
> Michael Tauson wrote:
>   
>> Most civilized civilian vehicles have 12 volt electrical systems these
>> days.  Much of the surplus I'd like to use aboard my all to civilized
>> Jeep requires 24vdc.  Building a small but mighty astable
>> multivibrator to handle the primary and an appropriately wound
>> secondary aren't a problem.  Where I do have a question or seventeen
>> is core material - and size, for that matter.
>>
>> I know some materials are expressly for power transformers but is
>> there any particular reason about any material can't be used for this
>> application?  Frequency shouldn't be an issue but are there materials
>> that might not like being in the presence of the currents that will be
>> presented?  Aside from needing space to feed the wires through, are
>> there any size requirements of note?
>>
>> I've read what I could find on the web.  Maybe the meds are messing me
>> up (They do that, you know.) but I couldn't find anything that
>> addressed these questions.
>>
>> ANy thoughts anyone?
>>
>> BEst regards,
>>
>> Michael, WH7HG
>>   
>>     
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-- 
Al Klase - N3FRQ
Jersey City, NJ
http://www.skywaves.ar88.net/