Some S American countries quote +/-10%, whether they actually do vary that much I don't know.
As for clocks - most nowadays are xtal controlled. The older mains dervied clocks certainly in the UK relied on the fact that the generating companies time averaged the frequency variation to zero over a 24 hour period........... as I recall All generators on a grid "slave" each other so they remain in sync - it's not a matter of getting two independent grids exactly in phase and then connecting them. C James -----Original Message----- From: Egon H. Varju [mailto:[email protected]] Sent: Monday, November 09, 1998 6:22 PM To: Paul Smith Cc: EMC-PSTC Subject: Re: Supply Frequency Variations At 09:22 AM 09/11/1998 +0000, you wrote: >Does anybody know or is able to point me in the right direction >for the supply frequency variations that the electric generating >companies expect/allow (both the UK and the US). I'm looking for a >percentage tolerance on the 50/60Hz nominal. In North America and Europe, indeed in most of the civilized world, the tolerance is essentially zero. This is why electric clocks are extremely accurate. The main reason is that most of these power grids are interconnected and the power companies sell power to each other. But the only way that you can connect two grids togethere is if they are EXACTLY in phase. If they were out of phase, you'd get a dead short. Yes, there are dc transmission lines, but essentially all connected power grids are exactly in phase, and are kept that way with painstaking accuracy. I find it very amusing when people insist on certifying their equipment for a range of frequencies, such as 47 - 63 Hz. This is somewhat silly since most equipment will never see anything other than exactly 50 or 60 Hz. Well, I suppose there is the odd country, or perhaps a private generator ... Cheers, Egon __________________________________________________________ Egon H. Varju, P.Eng. CSA Pacific Region Tel: 1-604-244-6640 HAVE MODEM - WILL TRAVEL Fax: 1-604-244-6600 E-mail: [email protected] [email protected] [email protected] __________________________________________________________ --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to [email protected], [email protected], [email protected], or [email protected] (the list administrators). --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to [email protected], [email protected], [email protected], or [email protected] (the list administrators).
