On 09 Jun 2008 09:55:39 GMT, Andrew Gabriel wrote:

and still more efficient even allowing for a motor-generator set to
create the 400Hz supply.

Er, I've never heard of an alternator that can produce a squarewave
output... Surely the physical nature of the beast (coils and magnetic
fields) means that the waveform is sine (or close to it).

Isn't the improved efficiency down to the higher frequency thus less
discharge of the reservoirs for a given load current?

--
Cheers
Dave.