Hello David:
Kindly accept my apology for apparently upseting you with my "Simple question"
in the Subject window.
I have no reason to dislike you and I stand better informed on such protocols
from your helpful reply - thank you.
My wish to keep this particular transformer is for the simple reason that it is
circa 1930 which is the vintage of AM tranmitter I am gathering parts to
make...( 227's in the speech section + 849 moded tube + 204 final using Hesing
modulation.)
I am striving to use as many contemporary components as is practical - and
affordable - in my circumstance.
>From another point of view, my nature is such that I would not discard the
>unit as it would provide me the opportunity to re-wind it...very much as a Ham
>in 1930 would consider doing too.
Thank you and the other kind folks in this fine group for assisting me in this
endeavor.
Warm regards to all,
Steve
WA2TAK
David Kirkby <david.kirkby@onetel.net> wrote:
>StephenTetorka@cs.com wrote:
>> Hi guys:
>>
>> I have a vintage filament xmfr.
>>
>> Voltages are a little high without load...and making allowance for 120 in
>> place of 110 ...and there is evidence of repair and sign of past leaking
>> resin.
>>
>> What the 'recommended' way to work up a full load - 10 Amps - to see if this
>> bugger can handle it?
>>
>> Tnx,
>> Steve
>> WA2TAK
>> _______________________________________________
>> Amps mailing list
>> Amps@contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>>
>>
>Can I make a simple suggestion - you pick a more appropriate title. Why
>not "testing filament transformer" or something like that? Then people
>will not have to read things they know nothing about. Archives can be
>searched in a sensible manner etc.
>
>Personally, given its condition I would try to get another and throw it.
>
>(At this point you really don't like me!!)
>
>Now to answer your question.
>
>The best test is going to be to find what the *maximum* heater current
>will be. That will not be the normal one, but worst case - i.e. look at
>the data sheet. Then get a resistor and load it up.
>
>R = Volts/current.
>
>Power = voltage * current.
>
>Given the power, which is likely to be 50-100W, it will need cooling. A
>100W resistor will need a heat sink. But I'm pretty sure a bucket of
>water would do fine. I have not tested it I must admit, but unless it
>boils around the resistor, which is most unlikely at that power, I think
>that would be fine. The resistor would not get too hot.
>
>If you have a decent heat sink to screw it to, then all the better. But
>for test purposes only, water will do. At that resistance, which will
>only be an Ohm or so, you need to be careful about lead resistance, so
>take that into account. Short the DVM leads and subtract whatever you
>get from the resistance you measure.
>
>Water is a bit conductive, but it will have negligable effect on a 1 Ohm
>ore so resistor. If it was 100k or more, then perhaps so.
>
>If you have a decent 4-wire meter, then it will be much more accurate,
>but I doubt you have that.
>
>But personally I would throw the transformer. If it shows sign of repair
>and leaking resin, I suspect it has been overloaded at some point. You
>have no idea how much damage it has done. It might work today, but next
>month it might be another story. If heater current gets removed from a
>tube, it is unlikely to do it a lot of good if running at full output.
>
>--
>David Kirkby,
>G8WRB
>
>Please check out http://www.g8wrb.org/
>of if you live in Essex http://www.southminster-branch-line.org.uk/
>
>
>
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|