Forum Home
PC World Chat
Thread ID: 141969	2016-04-03 22:41:00	Can a compass be affected (permanently) by a microwave oven?	John H (8)	PC World Chat

Post ID	Timestamp	Content	User
1418595	2016-04-08 02:18:00	Is it still under warranty? Unless there's a specific warning and advisement in the warranty concerning being under the microwave, you might have a shot here. Good thinking, lets hope it's a long guarantee as he bought it 15 years ago.	Cicero (40)
1418596	2016-04-08 02:21:00	Conversely .... www.trademe.co.nz	Cicero (40)
1418597	2016-04-08 03:03:00	Good thinking, lets hope it's a long guarantee as he bought it 15 years ago. If the warranty has expired - sue 'em! They should have informed the owner/purchaser about the possibility of microwave ovens swapping the polarity. Or they could at least give the owner some white and red nail polish to correct the errant confused needle!	SurferJoe46 (51)
1418598	2016-04-08 03:05:00	Conversely .... www.trademe.co.nz Wow! He bought it FROM A FLIGHTLESS BIRD? Tough toenails then.	SurferJoe46 (51)
1418599	2016-04-08 03:18:00	If the warranty has expired - sue 'em! They should have informed the owner/purchaser about the possibility of microwave ovens swapping the polarity. Or they could at least give the owner some white and red nail polish to correct the errant confused needle! If we all moved over there with the Syrians, do we all go auto mad as meat axes?	Cicero (40)
1418600	2016-04-08 04:20:00	Would a simple test be to place the compass near the microwave, turn it on & see if the compass needle moves? No, these are electrical-current pulse/timing & compass-point issues. Firstly, the E.M. pulse for switch-on or switch-off for the oven (the latter being more likely to cause the polarity change) must occur when the compass needle is correctly aligned for maximum effect, for example if it was parallel to the electromagnetic field i.e. at right angles to the coils, then it is possible that the compass would simply be demagnetised and wander aimlessly thereafter, whereas if aligned in parallel with the field source then it would cancel or reinforce the compass field depending on the timing of the transient magnetic pulse. It would be the switch-on pulse that dicked the compass, because that is high-current/low-voltage, while the switch-off pulse is low-current/high-voltage because there is no load to pass the current necessary to generate a magnetic pulse. There is likely to be some capacitive load, as was used in Kettering inductive discharge ignition systems to prevent high back-emf voltages from arcing across low-voltage points, but we are talking milliseconds here so you'd might not actually see any compass movement at all on switch on, or after the dirty deed was done. There is very little wriggle-room here, as the principles of electromagnetic induction and pole reversals etc are well embedded in electro-magnetic physics. You may be interested to know that the Earth's magnetic poles are not stable either, the North and South poles reversing locations many times during our planet's history, and they also wander quite a bit in modern times, but not sufficient to warrant recalibrating your compass. Cheers Billy 8-{)	Billy T (70)
1418601	2016-04-08 04:42:00	This begins to sound like a convenient shift in the time.space continuum is required to make it all happen. No, these are electrical-current pulse/timing & compass-point issues. Firstly, the E.M. pulse for switch-on or switch-off for the oven (the latter being more likely to cause the polarity change) must occur when the compass needle is correctly aligned for maximum effect, for example if it was parallel to the electromagnetic field i.e. at right angles to the coils, then it is possible that the compass would simply be demagnetised and wander aimlessly thereafter, whereas if aligned in parallel with the field source then it would cancel or reinforce the compass field depending on the timing of the transient magnetic pulse. It would be the switch-on pulse that dicked the compass, because that is high-current/low-voltage, while the switch-off pulse is low-current/high-voltage because there is no load to pass the current necessary to generate a magnetic pulse. There is likely to be some capacitive load, as was used in Kettering inductive discharge ignition systems to prevent high back-emf voltages from arcing across low-voltage points, but we are talking milliseconds here so you'd might notactually see any compass movement at all on switch on, or after the dirty deed was done. There is very little wriggle-room here, as the principles of electromagnetic induction and pole reversals etc are well embedded in electro-magnetic physics. I'm sure there's science going on here, but then again, the Las Vegas Odds makes it all too inconvenient to happen with any regularity at all, not to mention the first time. I've got a fiver on the magnetism just leaked out. And all this happened because it happened in Upsidedown Land, er - where it happened when it happened originally - where it happened to happen in a drawer happening under a microwave. Under "Replication laws of scientific probability" we get this c/p. If an experiment cannot be repeated to produce the same results, this implies that the original results might have been in error. In other words - if it's not reproducible - it's voodoo science. And that's all.	SurferJoe46 (51)
1418602	2016-04-08 10:38:00	This begins to sound like a convenient shift in the time.space continuum is required to make it all happen. Best you give it away SJ, I mean no offence, but you are seriously out of your depth, however this general class of EM phenomena occurs more often than you would think. To keep it 'in-house', how many times have computer users struck random corruption that a reboot clears? It happens relatively rarely, and is difficult to trace, but that is in part what I do for a living, and like all rare phenomena, such effects are almost impossible to duplicate without setting up a lot of technology to get it right, then being very very patient. In the 'compass' case it is a quite straight-forward phenomena that can happen at random, but one that I would find very time-consuming to repeat on an experimental basis, however that does not preclude a suitably qualified, equipped, and experienced person from identifying what the phenomena was and if necessary, determining how it might be avoided in the future. I have provided specialist electrical , electronic and electromagnetic diagnostic services to the NZ Military (Army) many Regional Hospitals, Universities, and factories large and small for over 20 years and I still get the call when the resident 'experts' have given up. I've four times lectured on such topics to major conferences in the US, and have provided specialist technical advice to the Supreme Court of New Jersey, so take my word for it, I've seen similarly rare and exotic effects in technology of all types, and most times I find the answer, but sometimes I don't. I have a wide range of diagnostic intruments to help me, but it is not easy, and even then, I don't always find the answer, but that is normal for any diagnostic process. Doctors' patients die, and sometimes only an autopsy can reveal the true cause of death. My most recent commission was to ensure that the operating suites in a large hospital for children (from birth through to adolescence) were free of interference from electromagnetic and electrical phenonena. My next commission is to validate the EM integrity of the new technology block at a major University. I've been involved in this project from the early planning stages, and now it is time to see if my recommendations for interference minimisation were followed, and I already know that some were not, but there is time in hand to remedy those omissions. I think that enough has been said on this matter, the electromagnetic 'mechanisms' by which the compass reversed polarity are nothing unusual, and could be duplicated if anybody was silly enough to waste enough of their time on it, but I am not. Nuff said.......... Cheers Billy 8-{)	Billy T (70)
1 2 3 4