INFO-VAX Mon, 17 Mar 2008 Volume 2008 : Issue 153 Contents: Re: Can a MicroVAX 3100 run on 208V? RE: Can a MicroVAX 3100 run on 208V? Re: Can a MicroVAX 3100 run on 208V? Re: Can a MicroVAX 3100 run on 208V? Re: Can a MicroVAX 3100 run on 208V? RE: Can a MicroVAX 3100 run on 208V? Peak cpu values in T4 different from ECP Re: Proof that macintosh is better than VMS Re: Proof that macintosh is better than VMS Re: Proof that macintosh is better than VMS Re: Proof that macintosh is better than VMS Re: Proof that macintosh is better than VMS ---------------------------------------------------------------------- Date: 16 Mar 08 18:42:18 EDT From: cook@wvnvms.wvnet.edu (George Cook) Subject: Re: Can a MicroVAX 3100 run on 208V? Message-ID: In article , glen herrmannsfeldt writes: > Tom Linden wrote: > (snip) > >> Yes, it does, we aren't as well standardised as the European there >> phase to phase >> (They don't have single phase AFAIK) 380V/sqrt(3) = 220 V > > That is the way I understand it, too. Three phase to homes. > You have to get more homes off a transformer, but at that > voltage it isn't so hard to do. Also, as I understand it > 50Hz was chosen when the transformer steel available wasn't > as good as US silicon steel. > >> I don't see how the Delta works unless that have a > >> separate winding, 240 phase to phase >> would need 208 phase to neutral. sqrt(3)/2 * 240 > > I have heard about, but never seen, a system that uses > three phase delta with the center tap of one of the > delta windings as neutral. The result is two legs > 120V from neutral, the other 208V, and 240V between > phases. The 208V one is called the wild leg. > Google for "three phase" "wild leg" and you should find > sites, such as www.3phasepower.org explaining it. I once did some work in a three phase breaker panel wired that way. Every third breaker position had 208V instead of 120V. Other than a notice in fine print, there was nothing at all to prevent a 120V circuit being wired to one of the 208V positions. A hassle to work with if you have a large number of 120V single pole breakers mixed with double and triple pole breakers; you end up having to move stuff around and using blank breaker position covers. George Cook WVNET ------------------------------ Date: Sun, 16 Mar 2008 19:26:02 -0400 From: "Dan Allen" Subject: RE: Can a MicroVAX 3100 run on 208V? Message-ID: <000301c887bd$194bdcf0$1f3a0681@sdct.nist.gov> > > I have heard about, but never seen, a system that uses three phase > > delta with the center tap of one of the delta windings as neutral. > > The result is two legs 120V from neutral, the other 208V, and 240V > > between phases. The 208V one is called the wild leg. > > Google for "three phase" "wild leg" and you should find > sites, such as > > www.3phasepower.org explaining it. > > I once did some work in a three phase breaker panel wired that way. > Every third breaker position had 208V instead of 120V. Other > than a notice in fine print, there was nothing at all to > prevent a 120V circuit being wired to one of the 208V > positions. A hassle to work with if you have a large number > of 120V single pole breakers mixed with double and triple > pole breakers; you end up having to move stuff around and > using blank breaker position covers. > > > George Cook > WVNET > Delta systems are intended primarily for use in large motor environments - not "house power" for 120V single phase lighting or appliances. It's quite common in industrial machine shops and agricultural settings at 440V for example. The NEC has very specific requirements for identifying the "wild leg" - color coded Orange I believe - if a neutral is provided. As with Delta systems, a Wye system also has wasted slot issues - you have to balance the 120V and 240V loads across all three phases as all phase imbalance current is carried by the neutral conductor. Three phase panels of both flavors are not simply plug and play. Failure to install the proper number of breakers of the appropriate types in the proper positions can be hazardous to your wiring's (and your personal) health. Dan ------------------------------ Date: Sun, 16 Mar 2008 16:57:16 -0800 From: glen herrmannsfeldt Subject: Re: Can a MicroVAX 3100 run on 208V? Message-ID: JF Mezei wrote: > While shoveling snow, I got to think... > In north america, one wire is basically the ground, another wire is +110 > V. So voltage differences between neutral and ground are near 0. > With a 208v setup from 3 phase, would there be any issues with the > "neutral" wire having a significant different from the ground on the > cabinet ? In many cases the one wire is used for both neutral and ground. This is common for electric stove/oven/dryer. (It might be that the code has recently changed.) I think it is also not unusual for three phase outlets. Otherwise, there is no reason neutral should be different for three phase. For 208V (using the common 240V three prong twist lock sockets) there is one wire for neutral and ground. As long as you can rely on that wire it should not be a problem. -- glen ------------------------------ Date: Sun, 16 Mar 2008 16:58:58 -0800 From: glen herrmannsfeldt Subject: Re: Can a MicroVAX 3100 run on 208V? Message-ID: George Cook wrote: (snip) > I once did some work in a three phase breaker panel wired that way. > Every third breaker position had 208V instead of 120V. Other than a > notice in fine print, there was nothing at all to prevent a 120V > circuit being wired to one of the 208V positions. A hassle to work > with if you have a large number of 120V single pole breakers mixed > with double and triple pole breakers; you end up having to move stuff > around and using blank breaker position covers. As I understand it, you are supposed to notice the orange wire. 120/208 uses black, red, blue, but not orange. -- glen ------------------------------ Date: Sun, 16 Mar 2008 17:03:15 -0800 From: glen herrmannsfeldt Subject: Re: Can a MicroVAX 3100 run on 208V? Message-ID: Dan Allen wrote: (snip) > As with Delta systems, a Wye system > also has wasted slot issues - you have to balance the 120V and 240V loads across > all three phases as all phase imbalance current is carried by the neutral > conductor. Three phase panels of both flavors are not simply plug and play. > Failure to install the proper number of breakers of the appropriate types in the > proper positions can be hazardous to your wiring's (and your personal) health. Normally the neutral should be able to carry the same current as any phase, so that unbalanced loads won't overload the wiring. It does make less efficient use of the transformer, though. There is one case where that isn't good enough. Some loads (such as discharge lamps) have a high third harmonic in their current usage. The third harmonic will add in the neutral between all three phases. One can get more neutral current than any individual phase. Larger neutral wire is needed in that case. -- glen ------------------------------ Date: Sun, 16 Mar 2008 21:33:51 -0400 From: "Dan Allen" Subject: RE: Can a MicroVAX 3100 run on 208V? Message-ID: <000701c887ce$f48579a0$1f3a0681@sdct.nist.gov> > -----Original Message----- > From: glen herrmannsfeldt [mailto:gah@ugcs.caltech.edu] > Sent: Sunday, March 16, 2008 9:03 PM > To: Info-VAX@Mvb.Saic.Com > Subject: Re: Can a MicroVAX 3100 run on 208V? > > Dan Allen wrote: > > (snip) > > > As with Delta systems, a Wye system > > also has wasted slot issues - you have to balance the 120V and 240V > > loads across all three phases as all phase imbalance current is > > carried by the neutral conductor. Three phase panels of > both flavors are not simply plug and play. > > Failure to install the proper number of breakers of the appropriate > > types in the proper positions can be hazardous to your > wiring's (and your personal) health. > > Normally the neutral should be able to carry the same current > as any phase, so that unbalanced loads won't overload the wiring. > It does make less efficient use of the transformer, though. > FWIW it's common practice in my area to use a "reduced neutral" - smaller than the phase conductors - on the assumption that on average the 120V loads are roughly balanced across the 240V conductors resulting in minimal current flow on the neutral. Neutral conductor size is only one of several reasons it is desirable to balance the phase loads in a 3 phase panel. > There is one case where that isn't good enough. Some loads > (such as discharge lamps) have a high third harmonic in their > current usage. > The third harmonic will add in the neutral between all three phases. > One can get more neutral current than any individual phase. > Larger neutral wire is needed in that case. > You learn something new every day... Dan > -- glen > ------------------------------ Date: Sun, 16 Mar 2008 17:10:05 -0700 (PDT) From: snaxau Subject: Peak cpu values in T4 different from ECP Message-ID: <28e3a8da-c46a-4876-83ae-298b16d90a65@s8g2000prg.googlegroups.com> Hi, I've started collecting both ECP and T4 data at 1-minute intervals recently and have noticed occasional T4 cpu busy peaks of > 99% while ECP does not record it for that period. But on the average, the T4 and ECP values do concur more or less. My theory is the ECP collector works at driver level and would record more accurate and reliable information while T4 uses MONITOR which is subject to process-level "noise" such as scheduling, etc. Is that a reasonable assumption? And can anything be done to reduce the spikes eg. give the T4 process higher priority or something? ------------------------------ Date: Sun, 16 Mar 2008 14:37:58 -0700 (PDT) From: AEF Subject: Re: Proof that macintosh is better than VMS Message-ID: On Mar 16, 9:44 am, AEF wrote: [...] Sorry to follow up on my own post, but I forgot to give credit to Feynman for the explanation of why you cannot even in principle predict which path the photon will take even if the LCD is ON. All I did was adapt it from the 2-slit experiment to this one (which is very similar). I include the introductory remarks and the diagram only for completeness. > > Here's an excellent example to drive the point home. I saw a talk > about this in graduate school in the late 1980's. Consider the > following experimental set up: > > F A B > > [-LASER-]-----|-------\-----------------\ > | | > | | > | - LCD > | | > | | > \-----------------\ > > C D [...] [Beginning of argument due to Feynman in Chapter 6 of The Character of Physical Law adapted from the 2-slit experiment to the one illustrated above:] > Now the question becomes: can you predict which path the photon will > take after passing through the beam splitter A with the LCD ON? Hidden > variable theory says you could do this by observing something at or > upstream of A. But if you could do that, then it makes no difference > whether the LCD is ON or OFF. Anything you observe with the LCD ON you > can observe with it OFF, and at the time of this observation, the > state of the LCD when the photon gets to it is still unknown. And if > you can successfully predict which path the photon will take, you > can't ever get the interference pattern with the LCD OFF, because an > interference pattern cannot be produced by photons traveling along a > single path, and an interference pattern is completely different from > what you would see if photons only traversed one path or the other. [I added the following and a few, small snippets in the part above relevant chiefly to this experiment.] > And there can't be any "secret communication" between the LCD and the > source or beam splitter at A because you can change the state of the > LCD AFTER the photon has passed through beam splitter A. [Back to Feynman's argument:] Therefore, > even with the LCD ON, there is no way to predict ahead of time which > path the photon will take if the apparatus is set up in such a way > that it can produce interference patterns with the LCD off. [End of adaptation of Feynman's argument. Below is a reference to the original.] Please see > Feynman's Chapter 6 of The Character of Physical Law (from which this > explanation is borrowed) for the full story (well it's the full story > at the layman's level -- if you know about how the wavelength of light > affects resolution, and are comfortable with the de Broglie relation, > you can go a little deeper, but the essential points are covered by > the layman's version -- for the deeper version, see Feynman's Lectures > on Physics. Also, Feynman's explanation is most likely clearer than > mine!). [...] AEF ------------------------------ Date: Sun, 16 Mar 2008 17:47:39 -0400 From: JF Mezei Subject: Re: Proof that macintosh is better than VMS Message-ID: <47dd958d$0$3931$c3e8da3@news.astraweb.com> AEF wrote: > F A B > > [-LASER-]-----|-------\-----------------\ > | | > | | > | - LCD > | | > | | > \-----------------\ > > C D Considering the wavelength of light, I doubt very much that you can setup a rig with mirrors where the A-B-D path is *exactly* the same length as the A-C-D path, down to a point where you may need to consider coriolis effect due to rotation of the earth. So when you wonder about interference being created, you need to first look at yourvery crude equipment such as the wave splitter and mirrors and the requireement that they be absolutely precicely positioned. Also, when going through the wave splitter, you'd need to ensure that the path FAC and FAB would go through the exact same amount of material in the splitter. (down to atomic level), and have exactly the same amount of refraction etc etc. Re: predicting whether a photon at A will turn right or go straigth: Just because it appears random to us and you can't really predict it doesn't mean there isn't a logic to it. If the photon hits a reflective atom at A, he will turn right towards C. If it passes between 2 reflective atoms, it will continue straight towards B. We may not have any equipment to see/measure this, but there is still some logic behind it, it isn't all "random". ------------------------------ Date: Sun, 16 Mar 2008 15:00:11 -0700 (PDT) From: AEF Subject: Re: Proof that macintosh is better than VMS Message-ID: <99384576-23c2-4f34-bc5a-267ee417ada2@t54g2000hsg.googlegroups.com> On Mar 16, 4:47 pm, JF Mezei wrote: > AEF wrote: > > F A B > > > [-LASER-]-----|-------\-----------------\ > > | | > > | | > > | - LCD > > | | > > | | > > \-----------------\ > > > C D > > Considering the wavelength of light, I doubt very much that you can > setup a rig with mirrors where the A-B-D path is *exactly* the same > length as the A-C-D path, down to a point where you may need to consider > coriolis effect due to rotation of the earth.\ It doesn't matter. The paths do not have to be the same length. You do need to set the apparatus up so that you get interference patterns with the LCD OFF. That's all. So when you wonder about > interference being created, you need to first look at yourvery crude > equipment such as the wave splitter and mirrors and the requireement > that they be absolutely precicely positioned. Also, when going through > the wave splitter, you'd need to ensure that the path FAC and FAB would > go through the exact same amount of material in the splitter. (down to > atomic level), and have exactly the same amount of refraction etc etc. No you don't. Why do you think otherwise? These things you bring up simply don't matter. Maybe it's not exactly 50-50. Maybe it's 49-51. So what? That doesn't change any of the results or conclusions. > > Re: predicting whether a photon at A will turn right or go straigth: > > Just because it appears random to us and you can't really predict it > doesn't mean there isn't a logic to it. If the photon hits a reflective > atom at A, he will turn right towards C. If it passes between 2 > reflective atoms, it will continue straight towards B. False. See part I of the video at http://www.feynman.com to see why. Also, if what you say is true you would never see an interference pattern because the photon has to travel BOTH PATHS to produce one. But you *do* see interference patterns with the LCD OFF, which is all that is necessary. Sorry, but you're just plain wrong. Please watch the video before responding to this. > > We may not have any equipment to see/measure this, but there is still > some logic behind it, it isn't all "random". The only logic is that the probabilities are computable via QM and that you cannot get an interference pattern from a photons that have traveled determinable paths. AEF ------------------------------ Date: Sun, 16 Mar 2008 15:05:32 -0700 (PDT) From: AEF Subject: Re: Proof that macintosh is better than VMS Message-ID: Correction to the laser-LCD experiment analysis (sorry): On Mar 16, 9:44 am, AEF wrote: > Hello, > [...] > Here's an excellent example to drive the point home. I saw a talk > about this in graduate school in the late 1980's. Consider the > following experimental set up: > > F A B > > [-LASER-]-----|-------\-----------------\ > | | > | | > | - LCD > | | > | | > \-----------------\ > > C D > [...] > > It gets better. The LCD can be switched ON or OFF rapidly enough so > that it can be switched AFTER the photon passes through A but BEFORE > the photon (if it's in the ABD path) reaches it (the LCD). You can > guess what happens. If you switch the LCD from OFF to ON while the > photon is in mid-flight, you lose the interference pattern. Some of > the photons traverse path ACD, thereby striking the LCD, and some ^^^ That should be ABD, of course. > traverse the path ACD. No interference is observed. If you switch it [...] AEF ------------------------------ Date: Sun, 16 Mar 2008 20:35:00 -0700 (PDT) From: AEF Subject: Re: Proof that macintosh is better than VMS Message-ID: On Mar 16, 4:47 pm, JF Mezei wrote: > AEF wrote: > > F A B > > > [-LASER-]-----|-------\-----------------\ > > | | > > | | > > | - LCD > > | | > > | | > > \-----------------\ > > > C D > > Considering the wavelength of light, I doubt very much that you can > setup a rig with mirrors where the A-B-D path is *exactly* the same > length as the A-C-D path, down to a point where you may need to consider > coriolis effect due to rotation of the earth. So when you wonder about > interference being created, you need to first look at yourvery crude > equipment such as the wave splitter and mirrors and the requireement > that they be absolutely precicely positioned. Also, when going through > the wave splitter, you'd need to ensure that the path FAC and FAB would > go through the exact same amount of material in the splitter. (down to > atomic level), and have exactly the same amount of refraction etc etc. > > Re: predicting whether a photon at A will turn right or go straigth: > > Just because it appears random to us and you can't really predict it > doesn't mean there isn't a logic to it. If the photon hits a reflective > atom at A, he will turn right towards C. If it passes between 2 > reflective atoms, it will continue straight towards B. This is the "reflective spots on the glass" theory. But it's not true because you can polish glass. It's also not true because you cannot get the observed interference patterns from spots. See the Feynman video to see why. > > We may not have any equipment to see/measure this, but there is still > some logic behind it, it isn't all "random". Nope. The whole point is that the photon does not take a definite path until you measure it with the LCD on. If that weren't true, you wouldn't get the interference patterns with the LCD off. If you could always predict which way the photon goes, it would take that definite path and you would never get the interference patterns with the LCD off. You simply cannot determine the path of the photon from A to D, either before or after it passes through the beam splitter A, and still get an interference pattern. Since the LCD can be switched while the photon is in mid-flight, you cannot determine a definite path for it until it reaches the LCD and only if the LCD is ON at that moment. Therefore, there is no way, EVEN IN PRINCIPLE, to predict which way the photon goes from A. It is not a limitation of our tools; it is a basic feature of Nature. It is a little like saying you can't divide by zero only because of a limitation of our computing skills. It is an intrinsic property of division. It's like asking what's north of the North Pole. To all readers: I'll not have Internet access for the next few days. I'll respond to any responses when I return. Take care. AEF ------------------------------ End of INFO-VAX 2008.153 ************************