Barry, Brownout is a fault condition. Alot of switching supplies operate in a range of 100 - 240 Vac 50/60 Hz. Supply Manufacturers usually specify operating temp and humidity conditions. So start by testing the Manufacturers own specification. 106 Vac already falls into the specified range. Per UL1950 1.6.5 Mains supply tolerance Equipment intended to operate directly from the mains supply shall be designed for a minimum supply tolerance of +6%, -10%. If the rated voltage is 230 V single phase or 400 V three phase, the equipment shall operate safely within a minimum supply tolerance of +10% and -10%.
This will increase your operating test range from 90 - 264 Vac. I go down to 85 Vac just because, I am a curious guy that wants to understand what my limits are and where they are. In any case, at these lower AC input voltages the PWM has to work harder to maintain a constant output voltage(s). In doing so there is usually increased heat activity associated with the PWM which can decrease the field reliability and MTBF which in turn equates to customer dissatisfaction. In Japan a 90Vac condition can exist. > -----Original Message----- > From: Bl Ma [SMTP:mbl...@yahoo.com] > Sent: Thursday, November 04, 1999 2:13 PM > To: mschm...@xrite.com > Cc: EMC/PS IEEE Group > Subject: RE: 90V & 47Hz - Is this a realistic combo > > Mark, > > Please pardon my ignorance. I have a silly question. > It seems to me that the purpose of brownout is to save > energy by reducing voltage. Why do you test your power > supply "down to 85 Vac at 50/60 Hz at the maximum > specified operating temperature with high humidity > conditions present" instead of "up to 106 Vac ..."? > Higher voltage would consume more energy and produce > more heat inside the power supply. > > Barry Ma > Anritsu > --------------------- > From: "Mark Schmidt" <mschm...@xrite.com>, on 11/4/99 > 9:45 AM: > > Eastern Japan Voltage 100 Vac @ 50Hz. (Tokyo, > Kawasaki, Sapporo, Yokohoma and Sebdai) > Western Japan Voltage 100 Vac @ 60Hz. (Osaka, Kyoto, > Nagoya, Hiroshima) > > I also agree with Tania and the brown-out conditions > that exist in Japan. It is my understanding that 90 > Vac is quite common, personally I would test down to > 85 Vac at 50/60 Hz at the maximum specified operating > temperature with high humidity conditions present. > ---------------------- > From: "Grant, Tania (Tania)" <tgr...@lucent.com>, on > 11/3/99 4:40 PM: > > Ages ago when I worked at another company that shipped > products to Japan, their unwritten rule was to design > in power supplies that operated without problems at 85 > Vac, and that had better be designed/tested down to 80 > Vac, because of the continued brown-out conditions in > Japan. It seems nothing much has changed. > > I don't remember what was stated about the frequency > tolerance. > > Tania Grant, tgr...@lucent.com <tgr...@lucent.com> > Lucent Technologies, Communications Applications Group > > > > > > > ===== > Barry Ma > __________________________________________________ > Do You Yahoo!? > Bid and sell for free at http://auctions.yahoo.com --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
