On 12/25/2015 11:25 PM, John Thornton wrote: > There is no transformer in there...
Ah, sorry about that... The second variable should then be considered, mains tolerance. The usual tolerance of the mains line is between +20% and -30%. If that seems large, it is. If you ask the company what you may expect, they will be very reluctant to give you an answer. The point is that the mains is geared to deliver a resonably constant frequency at the cost of voltage accuracy. The tolerance depends on topology and differs from where you are located from the nearest transformer, how many connections are shared on the transformer(s) and how the line is loaded along the way when it gets home to you. I actually measured the mains line at work once over a period of 7 days (15s interval) because we were having trouble with a mercury lamp that was not constant in intensity. The delivery company did not wish to be bound to any "hard" values and said that there is no guarantee for the actual voltage. They try to keep it within +/-15%, but cannot guarantee it due to line topology. The measurements I took showed very nicely how the grid "wakes up" in the morning and "enters sleep" in the evening. The voltage starts high early and starts to drop and jumps up whenever the delivery company adds a generator to compensate. The opposite happens late in the evening. The variability was arround the +/-15%. -- Greetings Bertho (disclaimers are disclaimed) ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
