Re: Tesla the man

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: FIFTYGUY@xxxxxxx 

In a message dated 4/27/07 12:29:14 A.M. Eastern Daylight Time, 
tesla@xxxxxxxxxx writes:
>> >International Space Station, which uses 120V DC power everywhere.
>>
>>     Why?
>
>spacecraft have generally used DC buses, historically 24VDC.

    I could see that because of commonality with military automotive 
components, and of course modern trend in industrial controls.

>But, higher bus voltages save a lot in IR losses, not only in the wiring
>harness (every gram counts in space.. costs a year's pay to get a
>kilo into orbit) but in the DC/DC power converter primaries.

    Of course. But I bet they don't double your salary if you manage 
to chop a kg off the design, eh? ;)

>So you want to go as high as you can without starting to get into 
two problems:
>a) voltage ratings on the semiconductor devices (sound familiar to
>you SSTCers?).. you want some serious margin so the device doesn't
>fail on a transient and/or a charged particle event

    Does a voltage margin save you from the unlucky cosmic ray?

>The solar panels on the station run at around 140VDC and it's
>converted to 120V for distribution,

    I was gonna guess that, but it sounded too easy. :)

    Thanks!

-Phil LaBudde






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