On 1 Jan 2017 05:07, "Chris Albertson" <[email protected]> wrote: > > Just a comment for anyone who wants to log line voltage v. time. If > you have an APC "Smart UPS" battery backup unit these will log voltage > and frequency to a file.
If the information is for your own use only, that is probably fine. But if you intend challenging the electricity supply company over it, I would use a laboratory multimeter with a valid calibration certificate. It will give your measurements far more credibility than the data from a UPS. I would suggest that a 5.5 digit laboratory multimeter with a current certificate from Keysight would be better than an 8.5 digit 3458A that is out of the calibration period by a day, despite the latter having lower uncertainty. The point where you measure the voltage is probably important too. Obviously wire resistance in a ring main reduces the voltage, so there's not much point reporting that the voltage is low unless measured at the point of the incoming supply. I suspect that it is better to measure there whatever ones cause for complete is. Possibly a motor run internally could act as a generator and push the supply above the incoming voltage. I don't know what (if any) averaging should be done. Does one sample every cycle? I would probably set my 3457A to sample 10 power line cycles (200 ms) here in the UK. I think collecting data every cycle would be a bit excessive, but maybe not. One can always post process the data later to do some averaging. What's the sample rate on your APC UPS? Dave _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
