[time-nuts] Where does 28V come from?

Roy Phillips phill.r1 at btinternet.com
Tue Jul 21 15:42:01 UTC 2009


abcde
----- Original Message ----- 
From: "Roy Phillips" <phill.r1 at btinternet.com>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Tuesday, July 21, 2009 12:04 PM
Subject: Re: [time-nuts] Where does 28V come from?


> Hal
> I think you will find that 28 volts DC is standard in many aviation and 
> military mobile equipment power requirements. It is the nominal battery 
> voltage that comes from two 12 volt cells in series that are fully 
> charged. The voltage to run such equipment is not critical (can be less 
> than 28 volts), as you normally charge two series 12 volt cells at 27.6 
> volts - this is indicative of the nominal voltage of such supplies. Trust 
> that this is the information you are looking for ?
> Roy Phillips.
>
> ----- Original Message ----- 
> From: "Hal Murray" <hmurray at megapathdsl.net>
> To: "Discussion of precise time and frequency measurement" 
> <time-nuts at febo.com>
> Sent: Tuesday, July 21, 2009 7:59 AM
> Subject: [time-nuts] Where does 28V come from?
>
>
>>
>>> That said, the modules also appear to be powered by 28VDC, add some
>>> regulation, you could use the chassis to power the Thunderbolt, and
>>> mount it in one of the blank panels.
>>
>> Lead acid batteries are close to 2V per cell.  For cars/trucks, they come
>> conviently packaged in 6V and 12V units.  The phone company works off 
>> 48V.
>>
>> But where does 28V come from?
>>
>> The Isotemp OSCO 127-10 data sheet says 27 V, but that's +3, -6 or 21-30V
>> which straddles both 24V and 28V.
>>
>>
>> -- 
>> These are my opinions, not necessarily my employer's.  I hate spam.
>>
>>
>>
>>
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>
>
>
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