Following opinions are mine alone, and were heavily influenced by my lunch-time burrito.
Looked at one about 10 years past and decided the design was, in my opinion, 'marginal' per scoped safety standards; but have not looked at any recent product versions. Not accurate for high crest-factor stuff, and some inductive loads gave it temporary insanity. Readings were usable and reasonable over a limited temperature range (probably because of the current shunt's tempco) and for specific load types. Many comments floating around the internet on this product, so there is probably a decent technical write-up available. Brian From: alfred1520list [mailto:alfred1520l...@gmail.com] Sent: Monday, February 12, 2018 2:34 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Current measurement While on the subject, any one familiar with the Kill A Watt meter? This listing sells for US$26 and free shipping: https://www.amazon.com/P3-International-P4460-Electricity-Monitor/dp/B000RGF29Q I swapped out the 2 mOhm current sensing resistor with a 0.2 ohm resistor (and of course greatly limiting the current capability) so I can measure standby power down to 10 mW. I did test with a 7 W incandescent light bulb and it reported reasonable readings. I tested are few phone chargers with nothing plugged and they idle at less than 50 mW. (But I don't know if I trust the figure down to decimal point:) It could be a really inexpensive way to get a reasonable (but not certification grade) power measurements. Best Regards, Alfred On February 12, 2018 1:36:10 PM PST, Brian O'Connell <oconne...@tamuracorp.com> wrote: Will admit to having done this stuff with using microcontrollers and discrete sequential data channels and of sufficient sampling speed, but am subject to frequent bouts of idiocy. And this was for process control, and thus not a Type Test. Also, note that there is a difference in technique and equipment between power loggers and an analytical instrument. Best done with an instrument intended for this measurement; that is 'power analyzers'. Typically found on shelves at Keysite, Tektronix (nee Voltech), Ametek, Chroma, etc. And many Tek and keysite DSOs have a 'plug-in' for doing power measurements. All of this instrument-grade stuff can easily handle external sensors. Brian -----Original Message----- From: Amund Westin [mailto:am...@westin-emission.no] Sent: Monday, February 12, 2018 1:05 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: [PSES] Current measurement If you want to calculate t! he consumed power (W) in a 1-phase AC circuit, you can use a current clamp-on device to measure the current in one lead/wire and multiply with the applied voltage. But with such a current clamp on device, to we measure the apparent power (VA) or the real power (W)? Best regards Amund Sent from my Android phone with K-9 Mail. Please excuse my brevity. - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
