Hello John, Johan, LF
16 2/3 Hz should probably be 16 1/3 Hz, one third of 50 Hz as John
pointed out.
Here in OH-land we use 50 Hz for the railways but during my EE
studies, the SM-land railway QRG was also mentioned for two reasons
(hope I remember this right now, it was about 25 years ago...):
- A lower frequency was selected to minimize the voltage drop caused
by the series inductance formed by the long overhead lines supplying
the locomotive.
- Initially 16 1/3 Hz was generated in rotary converters, for example
a 6-pole 50 Hz motor would drive a two pole generator which gives the
required step-down. Rotary converters need maintenance and so this
system was later replaced by non-mechanical devices such as
cyclo-converters or other early ways of electronic frequency
converters that supposedly require less maintenance. In fact, I think
this was the main reason for bringing up this subject in school.
BR
Paul-Henrik, OH1LSQ
Quoting Andy Talbot <[email protected]>:
Is that to minimise skin loss in steel track ?
UK Third rail is, of course, DC, and I once spent an idle moment
calculating the loss if 50Hz AC were to be used with magnetic iron
conductors. I think I came to the conclusion a 1MW train could probably
travel a few hundred metres before it lost its power supply.
andy G4JNT
On 17 March 2016 at 13:21, Johan Bodin <[email protected]> wrote:
Railway QRG is 16 2/3 Hz in Sweden too.
73 de Johan SM6LKM
John Rabson wrote:
I seem to recall that some railway systems use at about 16 2/3 Hz (one
third of 50 Hz) for traction.
...
Can someone say whether my recollections are correct, please?
73 John F5VLF
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