[ARC5] Slightly OT: Transformers

Thu Nov 28 15:05:25 EST 2013

Well Leslie, Id sure like to go back to Australia. I spent close to 8 months 
covering it all including Tasmania and Norfolk Island doing a broadband 
network installation management for Australia Telcom and computers for your 
national welfare offices. I absolutely loved the country, people, food, 
women, beer, except for your national obsession, Vegemite.....YUK! This was 
in 1984-85.

A side trip to NZ to do a 2 week network install for a brewery was icing on 
the cake.

Carl

----- Original Message ----- 
From: "Leslie Smith" <vk2bcu at operamail.com>
To: "Geoff" <geoffrey at jeremy.mv.com>; "ARC-5 List" <arc5 at mailman.qth.net>
Sent: Thursday, November 28, 2013 1:26 PM
Subject: Re: [ARC5] Slightly OT: Transformers

>  Helllo Carl,
>  The estimate (a graph) of VA v weight of the transformer is stuck on
>  the wall at our radio club here in New South Wales (Australia).
>  (That's the place to file useful info - on the wall at the radio club.
>   You'd be welcome to visit, take it off the wall and copy it.)
>
>  I've been told the graph was published in the ARRL handbook, so that's
>  likely the place it came from.
>
>  Your observations about current rating and circular mils is accurate -
>  it's been in the old hand-books (ARRL handbooks) for years.
>  The figure I remember is 750 cm per amp and that's 'bang' in the
>  middle of the range you give.
>
>
>  73 de Les Smith
>  vk2bcu at operamail.com
>
>
> On Fri, Nov 29, 2013, at 2:34, Geoff wrote:
>> Ratings vary from 500 to 1000 circular mills per amp depending upon the
>> quality of the steel used. The 500 rating goes back to the 30's and was
>> repeated for decades in the ARRL Handbook but in WW2 and later in
>> consumer
>> electronics materials improved.
>>
>> There was a posting somewhere of estimating the VA of a transformer by
>> measuring the core but I cant find it right now.
>>
>> Carl
>>
>> ----- Original Message ----- 
>> From: "Fuqua, Bill L" <wlfuqu00 at uky.edu>
>> To: "Eric Mynes" <kc8wzb at gmail.com>; <ARC5 at mailman.qth.net>
>> Sent: Wednesday, November 27, 2013 11:16 PM
>> Subject: Re: [ARC5] Slightly OT: Transformers
>>
>>
>> >  In the late 60's or 70's there was a multipage article in Electronics
>> > Magazine on power  transformers
>> > and how you can determine the rating of a transformer up to kW range. 
>> > The
>> > magazine is gone now
>> > but perhaps there is a URL that has the PDF of those magazines.
>> > 73
>> > Bill wa4lav
>> >
>> > ________________________________________
>> > From: arc5-bounces at mailman.qth.net [arc5-bounces at mailman.qth.net] on
>> > behalf of Eric Mynes [kc8wzb at gmail.com]
>> > Sent: Wednesday, November 27, 2013 6:10 PM
>> > To: ARC5 at mailman.qth.net
>> > Subject: [ARC5] Slightly OT: Transformers
>> >
>> > Greetings all,
>> >
>> > I have some questions about transformers and this seems to be the only
>> > group I'm in now that deals with tube rigs.  I hope you don't mind
>> > elmering
>> > me a bit by answering a few questions.  I mention slightly off topic
>> > because one day (hopefully soon) I'll start building a power supply to 
>> > use
>> > with my ARC 5 rigs, but for now, I just want to be able to power some
>> > basic
>> > homebrew tube transmitters.
>> >
>> > So, my questions go along the lines of...  I have several transformers
>> > that
>> > have followed me home from hamfests or someone has given me.  But most 
>> > are
>> > not labeled in any fashion as to what they are rated for.  As stated
>> > above,
>> > I'd like to build a small power supply that can run some homebrew tube
>> > rigs.  I might actually use some of the thousands of tubes that 
>> > followed
>> > me
>> > home from hamfests instead of leaving them piled in boxes with no use.
>> > I've tried googling any number or marking on the transformers trying to
>> > find a manufacturer or specifications and haven't had any luck.  How 
>> > can I
>> > test these safely as to not hurt myself or the transformer so that I 
>> > find
>> > out at least the voltages I should expect out of them?  Right now, I'm 
>> > not
>> > too concerned about finding how many amps they will provide as much as 
>> > now
>> > much voltage is on the end of the wire.  The number of amps question 
>> > will
>> > come soon though.
>> >
>> > Currently I have a transformer on my bench that has the following 
>> > markings
>> > 110v004h82
>> > 352052
>> >
>> > It appears to have 3 windings.  A black set (I presume is the primary), 
>> > a
>> > red set with CT, and a green set with CT.
>> >
>> > I'm kind of skittish at just applying 110v to the black wires and 
>> > seeing
>> > what the others have for voltages.  So, I figure why not ask some hams
>> > that
>> > might have a better clue than me.
>> >
>> > Please respond to me off the list as I don't want to waste too much of 
>> > the
>> > list's bandwidth on something that might be determined as an elementary
>> > question that we all should know.  I'll be quick to say that I'm a very
>> > much at an elementary stage on using HV and know enough to ask 
>> > questions
>> > before just trying things.
>> >
>> > Thank you for the bandwidth and Happy Thanksgiving to all
>> >
>> > 73,
>> > Eric
>> > k8ohz
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