{Collins} Re: Transformers Wanted

Well first,  in this application  not needing a neutral,  only ground,  you 
will only need 1 [ one ] xformer .. a .500 would do just fine ,  if I found 
a .750  I would get it ,  using the 12/24  or if 16/32  just depends how 
much BUCKING you want ,  225-230 vac is ideal for the 30s-1      in this 
instance you tie all the H wires in series 1-2-3-4 ... your 248vac power is 
applied at H-4 and X-1  presuming your going for the lower in either choice 
12/24  or 16/32   [  I have not seen this 9/16 voltage choice  {this to me 
would be a unique or more bastard size}   and it does not balance as you can 
see the 12/24 16/32 voltages do .. so i'm gonna presume this is not a real 
example  your 9/16 ...  so if you want to knock down this 248 to 230  get a 
16/32 and use the 16 in parell one end wired at the H-4 connection point...

draw your power for the 30s-1 from the H-4 tie point and the H-1 and X-4 
tie point..

in the perfect world you will see 16 less volts at this location than where 
your 248 vac input is,  yielding you about a 232 vac source for the 30s-1... 
your saturation will be reasonable good,  using a .500,  thus you might see 
a small voltage sag on loading or voice peaks at full power ..   where with 
the .750  or even 1kva  this saturation point will not be as demanding and 
you can see some ride thru of stability ..  { less sag, if any at all }  the 
.750  should do this need quite well,  and remember you wont really have a 
genuine neutral here, you will have the ability to see a neutral from your 
supply source,  but if you use it in conjunction with this buck scheme your 
gonna tear up the regulation you are trying to achieve, short answer dont 
use the neutral,  just ground it properly,   but you dont need it with the 
30s-1  { input neutral }....  even though on the inside it is offered a 115 
vac outlet for a 516f-2 if you so mount it on that shelf plate ..    i'm 
lazy and tired right now, but I think this voltage is developed within the 
main xformer in the 30s-1  but I can be wrong ..

lite fuz and stand back  ...  some go , some blow  ,   [ mac: humor ] 
seriously check this voltage along the way with you meter ...  and in 
closing,  this schematic is 1 of about 3-4 ways to set this all up..  so 
it's not the only way,  but it does work .. and well  ...  then finally be 
sure to adjust the filament voltage for the final PA tube ..  this is very 
easy in the 30s-1  it has it's own pot as I recall ..

Now the real bug a boo on the 30s-1 is the confusion Collins created by the 
wiring for using this on 115 or so voltage ..  this was all in the early 
days when it became recognized the importance of Neutral and the difference 
of the Ground,  but I am not going their this late / early, simple answer, 
run the thing on 230vac like it should be and call it good..  my brain is 
pretty spent and i'm gonna hang up my key board ..  73's  mac/mc  w5mc

BTW  these wiring schematics are availible all over the web pages ..  be 
sure and check this one i have outlined  ..

Located 46 miles due North of the Alamo, and 121 miles due South of the 
Western White House.   see my website at  www.collinsandharrisradios.com
----- Original Message ----- 
From: "James Thorusen" <entropycat@xxxxxxxxxxx>
To: "Mac McCullough" <w5mc@xxxxxxxxxxxxx>
Sent: Sunday, June 17, 2007 5:04 AM
Subject: Re: {Collins} Transformers Wanted

> Hi Mac!
>   Thanks for the data.   I have seen buck/boost transformers with 9/16 
> volt
> ratings, but they go for $200 or more each.... out of range for me right
> now, especially since I need a pair.
>   If you are familiar with the things, I have a question about them that
> perhaps you can answer.   The KVA ratings don't make a lot of sense to me.
> Normally, a transformer rated in KVA should, if it is a 12 volt 1 KVA
> transformer, be capable of about 83 secondary amps (1 KVA at 12 volts). 
> I
> presume that the KVA rating refers in this case to the load that is being
> bucked and boosted, and not to the transformer.   Therefore, I assume that
> the transformer has a lot of copper in the secondary winding, but not the
> iron or primary size that ought to go with that much copper.   In other
> words, 1 KVA at 120 volts is about 8.33 amps, and therefore the actual
> transformer power handling capability is 8.33 amps times 12 volts or about
> 100 VA.
>   Are the above assumptions and calculations correct?   I always have a
> hard time figuring out whether or not any given buck/boost transformer
> actually has enough copper in it to handle the current drawn by the 30S-1.
> Thanks,
> Jim T.
> entropycat@xxxxxxxxxxx
> ----- Original Message -----
> From: "Mac McCullough" <w5mc@xxxxxxxxxxxxx>
> To: <entropycat@xxxxxxxxxxx>; "AAACollins Mail List" 
> <collins@xxxxxxxxxxxxx>
> Sent: Sunday, June 17, 2007 12:44 AM
> Subject: Re: {Collins} Transformers Wanted
>> BTW  the more and about typical voltages for these are 12/24  or 16/32 
>> and
>> .500-.750 KVA is ample for your needs ..  the 750's and 1kva are most
> easily
>> the obtainable ..
>> Located 46 miles due North of the Alamo, and 121 miles due South of the
>> Western White House.   see my website at  www.collinsandharrisradios.com
>> ----- Original Message -----
> -- 
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> 12:50 PM

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