Re[2]:120V appliance on 240V supply
Robert, Yes of course! e.g. For entered 1 minute, timer expects 60, (3600 cycles), "Second Ticks" but on 50 Hz power receives only 50. Therefore "cooks" for another 10 ticks which takes 1/5 minute longer. Thank you for the correction. Tony, --Reply Separator--- Shouldn't that have been enter less time to get the same? As in enter 1:00 get 1:12? However, with the 50/60 of power being delivered, the time should come out the same for total power delivered. - Robert - --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
Re: 120V appliance on 240V supply
I would like to express my thanks to all of you who provided me with valuable information on this topic. I now have a good understanding of the possible risks associated with such an endeavor. Regards, Ravinder Email: ajm...@us.ibm.com *** Always do right. This will gratify some people and astonish the rest. . Mark Twain --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
Re: 120V appliance on 240V supply
I would think the clock timing and microprocessor timing would suffer and as a result it may deliver heat but programming prarameters could be drastically incorrect. For short periods of time the heating effects would be minimal but who knows what a safe time period would be. Better to have deisgned the trasnformers for 50Hz to begin with . Ralph Cameron EMC Consulting and Suppression of Consumer Electronics (After sale) - Original Message - From: "Ravinder Ajmani" To: Sent: Monday, May 14, 2001 11:48 AM Subject: 120V appliance on 240V supply > > > Hi, > I am interested in knowing if a 120V, 60Hz microwave oven can be safely > used on a 240V, 50Hz mains supply with a step-down transformer. > > Regards, Ravinder > > Email: ajm...@us.ibm.com > *** > Always do right. This will gratify some people and astonish the rest. > Mark Twain > > > > --- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ > > To cancel your subscription, send mail to: > majord...@ieee.org > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Michael Garretson:pstc_ad...@garretson.org > Dave Healddavehe...@mediaone.net > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > Jim Bacher: j.bac...@ieee.org > > All emc-pstc postings are archived and searchable on the web at: > http://www.rcic.com/ click on "Virtual Conference Hall," > > --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
RE: 120V appliance on 240V supply
This is a micro-wave right? This could explain why my wife burns my eats! (Please don't call her I have enough grief already) Gary -Original Message- From: Price, Ed [mailto:ed.pr...@cubic.com] Sent: Monday, May 14, 2001 1:57 PM To: emc-p...@ieee.org Subject: RE: 120V appliance on 240V supply Although this is not a safety concern, the timer may have it's clock derived from the powerline frequency. That would make the clock, and the timer function, run slow on 50 Hz. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military & Avionics EMC Services Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis >-Original Message- >From: wo...@sensormatic.com [mailto:wo...@sensormatic.com] >Sent: Monday, May 14, 2001 9:18 AM >To: emc-p...@ieee.org >Subject: RE: 120V appliance on 240V supply > > > >If the frequency rating of the product is 50-60 Hz, it should be OK. >However, if the rating is only 60 Hz, there may be the >following frequency >sensitive concerns: > >* Lower output from transformers due to insufficient core size >* Slower speed fans causing cooling problems (if ac fans) >* Higher ripple currents in the rectification filter >capacitors may >increase causing higher internal temperatures which will lead >to lower life >* Lower dc output from capacitor input rectification filter >* Decreased low-line tolerance > >Richard Woods > > -- > From: Ravinder Ajmani [SMTP:ajm...@us.ibm.com] > Sent: Monday, May 14, 2001 11:49 AM > To: emc-p...@ieee.org > Subject: 120V appliance on 240V supply > > > > Hi, > I am interested in knowing if a 120V, 60Hz microwave oven can be >safely > used on a 240V, 50Hz mains supply with a step-down transformer. > > Regards, Ravinder > > Email: ajm...@us.ibm.com > >*** > > Always do right. This will gratify some people and astonish the >rest. > Mark Twain --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall," --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
Re:120V appliance on 240V supply
Ravinder, Yes, been there, done that! (Kenmore 1980's Model). Used a 2kVA xformer w/ US style outlet strip for microwave and other US kitchen appliances. Only problem - Clock/Timer ran at 5/6 time so it was necessary to enter 1:12 for every 1 minute of cook time! (Perhaps some up to date models run clock from a crystal so wouldn't have that problem). Tony Firth,Electrical Eng., Quester Technology Inc.,Fremont,CA Reply Separator Ravinder Ajmani wrote: <... knowing if a 120V, 60Hz microwave oven can be safely http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
RE: 120V appliance on 240V supply
Although this is not a safety concern, the timer may have it's clock derived from the powerline frequency. That would make the clock, and the timer function, run slow on 50 Hz. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military & Avionics EMC Services Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis >-Original Message- >From: wo...@sensormatic.com [mailto:wo...@sensormatic.com] >Sent: Monday, May 14, 2001 9:18 AM >To: emc-p...@ieee.org >Subject: RE: 120V appliance on 240V supply > > > >If the frequency rating of the product is 50-60 Hz, it should be OK. >However, if the rating is only 60 Hz, there may be the >following frequency >sensitive concerns: > >* Lower output from transformers due to insufficient core size >* Slower speed fans causing cooling problems (if ac fans) >* Higher ripple currents in the rectification filter >capacitors may >increase causing higher internal temperatures which will lead >to lower life >* Lower dc output from capacitor input rectification filter >* Decreased low-line tolerance > >Richard Woods > > -- > From: Ravinder Ajmani [SMTP:ajm...@us.ibm.com] > Sent: Monday, May 14, 2001 11:49 AM > To: emc-p...@ieee.org > Subject: 120V appliance on 240V supply > > > > Hi, > I am interested in knowing if a 120V, 60Hz microwave oven can be >safely > used on a 240V, 50Hz mains supply with a step-down transformer. > > Regards, Ravinder > > Email: ajm...@us.ibm.com > >*** > > Always do right. This will gratify some people and astonish the >rest. > Mark Twain --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
RE: 120V appliance on 240V supply
Hi Ravinder, I have read the other replies that advise to check the voltage and frequency rating of the microwave's power supply. They also warn of the effects of changing power frequencies.All good advice. I have another concern to add. Remember the recent thread about single phase, split phase, two phase, three phase ...? Make sure that you know what "phase" or "polarity" of AC voltage your microwave was designed for. I don't want to give any more particular instructions since I don't know exactly what type of transformer you're using ... For me to recommend an actual wiring diagram without more facts would be foolish. (even by my standards, which are pretty low) All that I can say is use caution and make sure that you keep track of exactly which wires are floating and which wires are grounded. Some 120VAC devices don't care about polarity. However, some do!!! The microwave's designers may have made certain assumptions regarding the polarity of input voltage. Violating these assumptions could lead to an unsafe condition or an overstress on certain components in the microwave's power supply. I would be glad to correspond furthur (offline) about particulars. Best regards, Chris --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
Re: 120V appliance on 240V supply
They will deliver less powerabour 50/60 of what you expect. The power supplies in those ovens are quite inexpensive and use a single rectifying diode. When the voltage gets high enough, the microwave bursts on for a short time. Thus, if operated from 50 Hz instead of 60 Hz, the power will drop proportional to the frequency. Don't know about any deleterious effects that would cause concern. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Ravinder Ajmani To: emc-p...@ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Monday, May 14, 2001 9:24 AM Subject: 120V appliance on 240V supply > > >Hi, >I am interested in knowing if a 120V, 60Hz microwave oven can be safely >used on a 240V, 50Hz mains supply with a step-down transformer. > >Regards, Ravinder > >Email: ajm...@us.ibm.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
Re: 120V appliance on 240V supply
Hi Ravinder: > I am interested in knowing if a 120V, 60Hz microwave oven can be safely > used on a 240V, 50Hz mains supply with a step-down transformer. In essence, you are asking if a microwave oven rated for 60 Hz will operate safely at 50 Hz. I would guess that the microwave oven uses both a mains-frequency transformer and a mains-frequency fan. The problem is that of the quantity of iron in both the transformer and the fan. 50 Hz requires more iron to prevent saturation of the core. If there is insufficient iron, the devices will tend to overheat at maximum or even normal load. The fan will run slower. If the devices are conservatively designed, they will work okay, although without margin, at 50 Hz. Overheating of the transformer or the fan motor will initially produce an odor followed by smoke. I believe microwave ovens have an internal fuse, so this should operate before things get too hot. In addition, microwave ovens are in metal enclosures, so if a failure should occur, the fire is not likely to escape the enclosure. As a general rule, for electro-magnetic devices such as transformers and motors, you run a risk of failure when the frequency goes down. Best regards, Rich --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
RE: 120V appliance on 240V supply
If the frequency rating of the product is 50-60 Hz, it should be OK. However, if the rating is only 60 Hz, there may be the following frequency sensitive concerns: * Lower output from transformers due to insufficient core size * Slower speed fans causing cooling problems (if ac fans) * Higher ripple currents in the rectification filter capacitors may increase causing higher internal temperatures which will lead to lower life * Lower dc output from capacitor input rectification filter * Decreased low-line tolerance Richard Woods -- From: Ravinder Ajmani [SMTP:ajm...@us.ibm.com] Sent: Monday, May 14, 2001 11:49 AM To: emc-p...@ieee.org Subject: 120V appliance on 240V supply Hi, I am interested in knowing if a 120V, 60Hz microwave oven can be safely used on a 240V, 50Hz mains supply with a step-down transformer. Regards, Ravinder Email: ajm...@us.ibm.com *** Always do right. This will gratify some people and astonish the rest. Mark Twain --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall," --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
120V appliance on 240V supply
Hi, I am interested in knowing if a 120V, 60Hz microwave oven can be safely used on a 240V, 50Hz mains supply with a step-down transformer. Regards, Ravinder Email: ajm...@us.ibm.com *** Always do right. This will gratify some people and astonish the rest. . Mark Twain --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
