[NJARC] 48>96 doubler

[Jim Whartenby]

Steve
Re-wiring might be possible IF the 48 volt supply is floating and not referenced 
to the common safety ground used by the power supply AC plug.  The supply has to 
be floating or without a common connection to the safety ground so that when you 
connect both power supplies in series, you don't short out one of the 48 volt 
supplies.

I would think that you can check this out with an Ohmmeter.  The ground pin on 
the 120vac plug should have a very high resistance reading ( greater then a 
megohm or there about) with respect to the 48 volt common lead.
Jim



________________________________
From: "sgt88 at atlanticbb.net" <sgt88 at atlanticbb.net>
To: w2wiq1 at juno.com
Cc: njarc at mailman.qth.net
Sent: Fri, April 5, 2013 3:05:25 PM
Subject: Re: [NJARC] 48>96 doubler

Just remember
Reply = Poster
Reply All = Everyone

_________________________________________________________
Gents:

Sorry to make an "amp" out of a milliamp....

I wish to put together the least expensive AC powered 'battery 
eliminator'...small, compact and lighweight as well...

So far, it appears that I can the lower voltages in need - 5 or 6...and 48 
(45)...from one $6 computer power supply I mentioned previously.

That leaves only the 90 vdc that I need for my Stewart Warner 405...which I 
picked up 100% Beautifully restored!....which is why I'm focusing on this 
'challenge'...

My thought...( I don't need to warn you...I'm lacking skill )...is to get a 
SECOND separate $6 computer power supply putting out a second 48 
vdc...and...re-wiring it...with the proper diode circuitry...to double that 48 
to 96..with a voltage dropping resistor to get my 90...IF...the radio does not 
load the power supply below that 90...ditto for the lower voltages...will not 
know that till I plug it in...

Yes...there are other ways to accomplish it...as already posted...

But...I can fit those small computer supplies INTO the cabinet...( my other 
concern is heat buildup...which may cause the temperature 'fuse' to blow that 
MAY be wired into those computer transformers...IF they are employed at all...if 
not..may have issue to fire safety issue...then I'll have to put them outside 
the box...

Mucho graciano,
S.



On Fri, 5 Apr 2013 18:21:42 GMT
"w2wiq1 at juno.com" <w2wiq1 at juno.com> wrote:
>   HI STEVE:
> 
>   I SUGGEST PICKING UP AT A GARAGE SALE,FLEA MARKET OR HAMFEST A COUPLE OF 
>THOSE 3-1/2 OR 4AMP CB SUPLLYS FOR 5 OR 10 BUCKS.IF THERE IS ROOM FOR 2 
>TRANSFORMERS IN ONE CABINET AFTER STRIPPING OUT THE PARTS THAT IS THE FIRST 
>STEP.CONNECT THE LOW VOLTAGE WINDINGS TOGETHER AND MEASURE THE PRIMARY 120V 
>SIDE.THEN REVERSE THE 120V TO THE OTHER TRANSFORMER AND SEE WHICH WAY IT WILL 
>GIVE YOU THE LOWEST VOLTAGE.THEN YOU CAN USE A VARIABLE VOLTAGE REGULATOR 
>CIRCUIT TO ADJUST IT FOR 90V.I WOULD USE A BRIDGE RECTIFIER OF SEVERAL AMPS 
>WHICH SOME TIMES CAN BE FOUND AT THE HAMFESTS.I DO NOT KNOW IF RADIO SHACK WOULD 
>HAVE ONE OVER AN AMP.
> 
>   AS AL EXPLAINED YOU CANNOT USE THE COMPUTER POWER SUPPLY.
> 
>   WALTER-W2WIQ
> 
>   ---------- Original Message ----------
>  From: <sgt88 at atlanticbb.net>
>   To: <njarc at mailman.qth.net>
>   Subject: [NJARC] 48>96 doubler
>   Date: Fri, 05 Apr 2013 13:17:36 -0400
> 
>   Just remember
>   Reply = Poster
>   Reply All = Everyone
> 
>   _________________________________________________________
>   Hi Al:
> 
>   Was wondering if could add/arrange some diodes to make the doubler?
> 
>   Steve t
>   ______________________________________________________________
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