Hello All.
The safty issue stems from the fact that it requires about 32 volts DC
to maintain a plasma arc in air. If 18 lead acid cells are used , the
charging voltage is 2.33 X 18 = 42 and the discharge would fall below 32
under a short.
THis equates to a 14 volt charge on a 12.6 volt lead acid and a 10.6
volt discharge. Lead acid maintains it discharge voltage in the 12 to
11 volt range so there could be some reasonable damage until the arc
fell out. Raising it to 48 volts would make it exponentially worse.
---
Ron
Steve Thompson wrote:
>
> Joe wrote:
>
> >Why on earth would they use 42 Volts instead of the 48 Volt systems
> >already in use in many other platforms? 42 volt systems will require
> >a new set of development as opposed to the COTS (commercial off the shelf)
> >solutions already available. Being 3.3 volts, the microprocessor controls
> >will require DC-DC converters in any case ...
>
> A possible reason is that worst case voltage in a 48V system is higher than
> 50V which, I think, has implications with safety directives, at least in
> Europe. With the 42V option, you have to get to the equivalent of 16.7V in a
> 12V system to reach that safety point.
>
> Steve
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
|