On 07/07/2013 18:19, John Williamson wrote:
Andy Bartlett wrote:
"John Williamson" wrote in message
Another way to save money on the grid would be to increase the
frequency, allowing the use of smaller transformers for the same
power. The same objections apply, although aerospace applications
often use 400Hz AC for this reason.

Trouble is even though substation efficiency would increase, your main
transmission line losses will increase dramatically due to skin
effect. It is still significant even at 50Hz.

Conflicting requirements. DC is best for long distance transmission, and
HF AC for smaller transformers...... It's Edison vs. Westinghouse all
over again. Grin

Or, in Britain, Crompton, Kelvin and Hopkinson v Ferranti, Mordley and
Thompson.

Could this be the reason why we use 50 - 60 Hz worldwide, as the best
compromise for a national grid?

Possibly something to do with 40Hz being about the minimum frequency at
which flicker was not noticeable to most people with early incandescent
lamps. There being a limited number of manufacturers in the world making
generating equipment was probably also a factor.

In Britain, in 1930, there were 15 different AC frequencies in use, from
25Hz to 100Hz, but 81% of all generation was at 50Hz. Standardisation
cost £17.5 million.

Colin Bignell