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Cursitor Doom <curd@notformail.com>: Aug 01 12:31PM Does anyone know how tolerant these are to over-voltage? For example, would one rated at 250V be able to handle 260V - 265V for a minute or so?   thanks.

MJC <gravity@mjcoon.plus.com>: Aug 01 05:18PM +0100 In article <mpie6h$3pq$1@dont-email.me>, curd@notformail.com says...   > Does anyone know how tolerant these are to over-voltage? For example, > would one rated at 250V be able to handle 260V - 265V for a minute or so?   > thanks.   Electric eel?   Mike.

"Ron D." <Ron.Dozier@gmail.com>: Jul 31 08:54PM -0700 Phil: > Scopes have a lot of errors.   ** That's a a bit harsh.   Analog scope days and having error sources and effects drilled into my head. I just really wanted to say, know what your error sources are. At one point in my life numbers like 2E18 and 7E18 were considered "essentially the same".

Cursitor Doom <curd@notformail.com>: Aug 01 01:46PM Just one final point. Is a single sine wave sufficient, or will it have to be two, harmonically-unrelated sine waves? ISTR with RF power measurements you need to perform the slightly more complicated 'two-tone' test; just wondering if the same applies at audio frequencies?

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net>: Aug 01 11:17AM -0400 On 07/31/2015 11:54 PM, Ron D. wrote: > my head. I just really wanted to say, know what your error sources > are. At one point in my life numbers like 2E18 and 7E18 were > considered "essentially the same".   Former astronomer?   Cheers   Phil "also a former astronomer" Hobbs   -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics   160 North State Road #203 Briarcliff Manor NY 10510   hobbs at electrooptical dot net http://electrooptical.net

jurb6006@gmail.com: Jul 31 08:18PM -0700 One has come in to our realm. We do some high end audio so having something like this desirable. It was bought surplus on the cheap. It is not dead, but I am pretty sure it is not working correctly. I've yet to completely learn to work the thing actually, and am taking it slow.   First off, I DO know the basic tenets of a distortion meter. It filters out the fundamental frequency and measures what remains. Not quite rocket science. Unfamiliar territory for me indeed, but I should be able to understand this.   I am looking for failure modes, tips on operation and basic self checks and so forth. I have only gotten so far in the manual but I am on it. The way I see it, these things you take a sine wave, put it through whatever and calibrate the distortion meter somehow. Like set it to full scale, flip the switch and you get the distortion reading.   I cannot get it to act right, at least what I think shoud be right. I have actually confirmed that it does detect distortion. Instead of the onboard oscillator I used my Wavetek 111. Not the greatest but good enough for what I wanted to do. I got the thing to give a useful meter indication and switched waveforms. I switched to triangle from sine and the needle didn't go up. OK, now realy I am not sure if the peak/RMS value of a triangle wave is less or more than a sine wave. And I fully expected the square wave to peg the meter, which it did.   Until I hit this other waveform on it, looks like _/|_/|_/| and saw the needle rise could I be sure this thing is anywhere near being able to really measure distortion. I don't care what, that half sawtooth with the 50 % dead time will deflect any measuring device less whether it measures average, RMS, peak or smegma. PLUS the thing is only positive going, so the peak value is half. And yet the needle moved up.   I consider that a good sign. The Wavetek 111 info is available at BAMA if you want to really see the waveform. And it is that waveform like, exactly.   Another thing I am noticing is that when you change certain settings the needle pegs and takes a few seconds to settle back down. Now, with HP I am not impressed. some of their designs, certain other things and their ideas of the human interface, I think suck. but the fact is they built this, not me and no matter what I think about some of their dowside, I do not bleieve they designed the thing so it would peg the meter on things like range changes. Mode changes. Like from input to distortion.   We did a quick visual on it, there is nothing spilled inside, no burn marks, bulging caps or anyhing of the sort. Of course this is going to be done again but we stuck the lid back on to see how it works.   Other thing is that it has some broken knobs. I can deal with that until some come along, as long as the thing works.   But really, ike known good test ways ? I am not talking MBS here, just a basic test. Like if I switch from sine to square, is there a number that it should read like 50 % or something ? I mean like at a standard say 1 KHz and a specified rise/fall time. Can we get close somehow ? Like if you buy a used ohmmeter off someone that is supposed to work you would take a resistor and check it to see the thing actually works.   Actually a test like that is what I am really after. And of course whatever else might help this thing stay out the dumpster. Calibration attempts later.

jurb6006@gmail.com: Jul 31 08:37PM -0700 MBS = NBS     Why they put them letters right next to each other ?

Phil Allison <pallison49@gmail.com>: Jul 31 09:23PM -0700 > Other thing is that it has some broken knobs. I can deal with that until some come along, as long as the thing works.   > But really, ike known good test ways ? I am not talking MBS here, just a basic test. Like if I switch from sine to square, is there a number that it should read like 50 % or something ? I mean like at a standard say 1 KHz and a specified rise/fall time. Can we get close somehow ? Like if you buy a used ohmmeter off someone that is supposed to work you would take a resistor and check it to see the thing actually works.   > Actually a test like that is what I am really after. And of course whatever else might help this thing stay out the dumpster. Calibration attempts later.     ** The HP339A is a high performance, auto-nulling THD analyser, capable of resolving 0.001% distortion.   To test it you *must* use the internal low distortion oscillator and set the unit to auto null at say 1kHz. After a few seconds the reading should fall to around 0.001 or 0.002%.   Pegging the meter is not a fault, until the auto nulling system has finished its job large amounts of fundamental frequency get through the notch filter/s and the meter is simply showing you that fact.   It is very instructive when using a THD analyser to view the residual signal on a scope - so you know what it consists of.   Might be mostly AC hum, random noise, second harmonic or crossover distortion spikes - or a mix of some or all the above.       .... Phil

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net>: Aug 01 11:15AM -0400 > Actually a test like that is what I am really after. And of course > whatever else might help this thing stay out the dumpster. > Calibration attempts later.   One simple method is to wire up a comparator to turn the internal oscillator signal into a square wave.   The fundamental component of a 1V amplitude square wave (2V p-p) is 4/pi volts, and the THD is everything else. The THD is sort of a voltage ratio (it's the square root of the power ratio), but whatever it is, the impedance divides out, so for simplicity let's figure based on 1 ohm impedance.   Total power = (1 V)**2 / 1 ohm = 1 W   Fundamental power = (4/pi)**2 / 2 = 0.81 W   Thus   Harmonic power = 0.19 W   and   THD = sqrt(0.19/0.81) = 48.4% (*)   You can take that and add it to the original sine wave via voltage dividers (a decade resistance box would be useful), and calibrate the meter down as low as you like. 90% sine + 10% square = 4.84% THD, etc.   Watch out for the comparator pushing crap back out its input, which can be a problem at very low levels.   Note that because they use a notch filter, these meters measure THD+noise, not just THD.   Cheers   Phil Hobbs   (*) Another definition of THD is sqrt(harmonic power + noise power)/(total power), which for a square wave would be sqrt(0.19/1) = 43.5%. Doesn't make much difference at tolerable distortion levels.   -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics   160 North State Road #203 Briarcliff Manor NY 10510   hobbs at electrooptical dot net http://electrooptical.net

Beloved Leader <Kim_Jong_Il@volcanomail.com>: Jul 31 12:12PM -0700 On Tuesday, April 28, 2015 at 6:32:21 PM UTC-4, mike wrote: > Been fixing wall warts and laptop batteries. > I'd normally glue them back together with the > stuff used for plastic plumbing.   I open up those wall warts every now and then. When I've finished doing whatever it was that I opened them up for, I put them back together with contact cement and dental floss. The contact cement goes on the seams. Then I wrap the two halves with about six windings of dental floss and tie the loose ends in a knot You won't be able to pull the two halves apart.   Dental floss is pretty strong stuff. Think: how many strands of dental floss would be needed for you to support your weight were you to hang, with a gloved hand, from a tree limb or football goalpost? Not that many.

dansabrservices@yahoo.com: Jul 31 04:15PM -0700 I have used GC Electronics Service Cement successfully.   Plastic Weld by Plastruct works well too.   Dan

mike <ham789@netzero.net>: Jul 31 10:38PM -0700 > I have used GC Electronics Service Cement successfully.   > Plastic Weld by Plastruct works well too.   > Dan   Anybody tried Bondic? Looks interesting, but not $22 interesting.

M Philbrook <jamie_ka1lpa@charter.net>: Jul 31 02:47PM -0400 In article <1e2c15cf-b258-48ec-a2bc-d045a026e3e3@googlegroups.com>, pallison49@gmail.com says...   > Seen a few cheap Chinese fans with tight/stuck bearings - takes a fair bit of solvent to get them spinning again.   > The OP has no so far bothered to open a fan a check the motor wiring for continuity.   > ... Phil   Yes he did, There is no continuity.. Which means it's been operating hot!   Jamie

petrus bitbyter <petrus.bitbyter@hotmail.com>: Jul 31 09:06PM Deane Williams <pyroartist.dw@gmail.com> wrote in > capacitor it tests OK. > Thanks for any ideas. I am going to switch over to a mechanical relay.   > Dean     So you blew some fans. But what about the SSR? Is it suited for diving these motors? Some properties are as important as properties of a mechanical relay and even with the right specs it may be defective.   Then, what about the signal diving the SSR? If it comes from a mechanical switch, the contactbounce can damage or destroy the SSR which in turn can blow the motor(s). SSRs like to be driven by clean signals and tend to be much more unforgiving them their mechanical couterparts.   petrus bitbyter

Phil Allison <pallison49@gmail.com>: Jul 31 07:42PM -0700 M Philbrook wrote:   " The motor still spins easily. There is no DC continuity from the power plug but I beleive this is normal for induction motors? "     >> The OP has no so far bothered to open a fan a check the motor wiring for >> continuity.   > Yes he did, There is no continuity..     ** ".. from the power plug ... ".   Box fans typically have timers, 3 way speed controls and tilt switches, any of which could be the real problem.     > Which means it's been operating hot!   ** Not likely with perfectly free bearing and no damage.     .... Phil

John Robertson <spam@flippers.com>: Jul 31 09:34PM -0700 On 07/31/2015 7:42 PM, Phil Allison wrote:   > ** Not likely with perfectly free bearing and no damage.   > ..... Phil   Hi Phil,   I don't think anyone read my quote (July 29) from a SSR (Omron) manufacturers' FAQ PDF about using non-motor rated SSRs with induction motors. As they said, as long as the SSR has sufficient rating to handle the start up current (etc.) there will be no problems for the SSR.   The only thing folks haven't considered is a voltage surge - that could take out the fan without harming the SSR. The wiring may have problems where the neutral fails in a sub-box leading to 240VAC going to a motor designed for 120 - the motor would not last long, yet wouldn't give obvious signs of failure as the internal overheat fuse would open quickly...   I have no other ideas unless he isn't giving the house elves enough food and clothing.   John :-#(#   -- (Please post followups or tech inquiries to the USENET newsgroup) John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games) www.flippers.com "Old pinballers never die, they just flip out."

ajeshtholoor@gmail.com: Jul 31 12:44PM -0700 On Thursday, August 14, 2008 at 10:45:26 PM UTC+5:30, NVT wrote: > Hi, > I am looking for datasheet of IC STK 403-100 > Thank you   I am looking for datasheet of IC STK 403-100

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