Thread: Why 28V DC?
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Old January 14th 04, 03:24 PM
Roger Hamlett
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"Bob Martin" wrote in message
om...
I'm working in the avionics integration test facility at Gulfstream...
one of the engineers had a question for me (being an airplane person
instead of an electrical/computer guy) that I couldn't answer... why
do airplanes use 28V DC systems (or 14V)? He says most industrial
applications use 24V DC. I tried googling on it but nowhere did it
suggest any reason why, just that it is.

Battery voltage.
The '12v' electrics on your motor car, actually run at typically 13.8v
(normal charging voltage of 6 lead acid cells). Hence much '12v' electronics
is 'mislabelled'. On aircraft, the naming was made to co-incide better with
the real voltage present.
In fact much industrial electronics running on '24v', is also a 28v system
(whenever the system has a lead-acid standby ability).

Best Wishes