Armed Polite Society
Main Forums => The Roundtable => Topic started by: 280plus on August 29, 2011, 04:00:45 PM
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Do any of you computer people know if there is a way to monitor the A/C frequency coming into my windows based clone here? I got a boiler here telling me it doesn't want to run because the frequency is not right so I'm curious as to what it is coming off this generator. As it is the 240V outlet is pushing 260 V but I don't know if it's because generators do that or it's effed up somehow or bercause it had no load on it. 125V each leg to neutral. frequency issue doesn't seem to bother the computer.
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Computers don't have any real provision to monitor incoming line power. The powersupply deals with it and provides DC to the actual computery parts.
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My DMM measures freq. Short of that I don't know of many handy things that could do that.
Do you have a digital timing light, or portable tach that you could measure Genset RPM with? You could get find freq pretty easy with that.
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Do any of you computer people know if there is a way to monitor the A/C frequency coming into my windows based clone here? I got a boiler here telling me it doesn't want to run because the frequency is not right so I'm curious as to what it is coming off this generator. As it is the 240V outlet is pushing 260 V but I don't know if it's because generators do that or it's effed up somehow or bercause it had no load on it. 125V each leg to neutral. frequency issue doesn't seem to bother the computer.
Make sure the generator is set to 60 hz and not 50. Some generators made for the global market are switchable. If it's set for 240 I could see someone having dorked up the frequency setting by simply not knowing.
Brad
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Any decent DMM can read frequency. Also, very few things actually care about incoming frequency anymore. What is this "boiler" device that you have?
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Ask Kenneth?
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Ask Kenneth?
Dammit! You beat me to the punchline. (I guess one has to be quick around here)
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I'm going to guess you've tried restarting the boiler. Some boards read the freq when you power them up. Sometimes killing power and restarting will get it back to reading right.
jim
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Paspifically it's a Triangle Tube "Excellence". I did retry. My thought is to disconnect everything else from the gen and see if it works then. Maybe a frideg motor or something is effing it up. No way to adjust frequency on the gen that I can see.
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Turns out TT boilers won't run on a generator unless you get a magic TT box and put it between the gen and the boiler. :facepalm:
:laugh:
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Does the generator deliver a sine wave? I guess most of them nowadays are square-waves generated by a converter. If may be sensing all the harmonics of square waves and deciding it isn't 60 Hz.
I think (I'd have to think about it) if your meter measures frequency, it may also measure duty cycle, and I think (again, I'd have to think about it) the duty cycle can tell you whether it's close to sine or close to square.
Just guessin'.
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Wire a speaker directly into an outlet (add a resistor...) and then record the noise the speaker makes with a microphone attached to your computer's sound card. You can then evaluate the frequency with any number of freeware audio programs.
=)
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(add a resistor...)
A low wattage light bulb might work well there for a resistor. I've used one of those 7 1/2 watt night light bulbs to drop voltage. Their hot resistance is around 1600 ohms. Which would be about 70 ma, thinking DC. That's less than one watt for a 16 ohm speaker in series with the bulb, which any speaker ought to be able to handle.
If my 'rithmetic is right.
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Wire a speaker directly into an outlet (add a resistor...) and then record the noise the speaker makes with a microphone attached to your computer's sound card. You can then evaluate the frequency with any number of freeware audio programs.
=)
Short of using a piezoelectric speaker, I don't think this will work. I'd expect that the physical inertia and magnetic capacitance to smooth out a square wave.
...Might have to try it tonight with an oscilloscope and function generator.
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Yeah, I wasn't thinking about the speaker's own inertia and physical dwell time removing the square wave information.
I just am well acquainted with what 60Hz sounds like, from my misspent youth and lots of ill conceived electrical experiments.
I just know you can use a sound card and a little math for damn most anything, even as a chronograph for ballistics, if your target is noisy enough. =D
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yes, my kingdom for an oscilloscope right about now.
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yes, my kingdom for an oscilloscope right about now.
Too bad you're not closer to me, I'd lend you my bk precision 2520.
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Sticking your finger in the socket with a pedometer enclosed in your other hand so you shake it for a minute, and count the "steps" is out of the question, huh?
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Just a thought, variation on the speaker idea, speaker on the line (with resistor as suggested, but easier would be a cheap 120/12 step-down transformer you can get from a wide variety of places) would give you a power line frequency tone, then just play a 59hz (or 61hz) tone from your computer speaker and snap yo' fingers to the beat...you get a 1hz beat for both, it's a 60hz line frequency.
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Too bad you're not closer to me, I'd lend you my bk precision 2520.
Where are you again? =D
The square wave theory sounds pretty plausible. I could always call them. Should have done it today.
What I DID do is tie 3 separate loops of twisted steel cable from the generator to the garage door frame inside to make it a little more difficult to steal the thing. Everybody else seems to be getting their power back so we're hoping it won't be much longer. Still no cable. I'm stressin' man. :'(
:laugh:
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If it's a waveform problem, wouldn't an isolation transformer smooth it out? (by attenuating the high frequency harmonics)
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If it's a waveform problem, wouldn't an isolation transformer smooth it out? (by attenuating the high frequency harmonics)
This, or actually any induction load.
Got a 1/2 hp PSC motor sitting around? Tie it in to the circuit, in parallel with the boiler.
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I think an inductive load in parallel would make it worse. You'd need a choke (inductor) in series or a capacitor in parallel. A resistive load, like a waffle iron, in parallel might help.
I also wonder if the problem has nothing to do with frequency and it's really a floating ground? Is the frame of the generator bonded to earth ground?
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Put a UPS between the gen and the unit. This should clean up the wave and let it run.
jim
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Put a UPS between the gen and the unit. This should clean up the wave and let it run.
jim
Eh? All the consumer grade UPS's I've run across just pass the current through metal oxide varistors when not in battery mode. Line conditioners, yes, but those are expensive, uncommon, and heavy! Have you run across some UPS equipment that has some provision for frequency correction?
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All computer power supplies are capable of accepting frequencies of 50,60, and variations thereof, so I wouldn't worry. They all transform it down to a lower voltage, rectify, and pass through multiple high frequency switching regulators, so really, it doesn't matter what is put in, unless it's a really old system. The same is not true for some power bricks (ESP. Older ones).
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well, we're finding that the plug in digital clock gains time now. Resulting assumption is the gen frequency is higher than 60, Doesn't seem to affect anything else. I'm most worried about smoking the well pump but it seems to be working just fine.
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Hm! Using the plug-in digital clock to check frequency is a good idea! I gotta remember that one.
You can even calculate the actual frequency from the time gained or lost and the length of time of the test period....
Not baaaaaad.
Terry, 230RN
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It also sputters a bit. I figure it's running rich. I call my local small engine repair place. Won't work on colemans, cant get parts for them. I said, well can't you just take it, change the oil and tune it up? "Nope, because that always leads to something else and I don't want to deal with it." Sweeeet,,,
I hereby rescind my plug for Coleman Generators. =D
I'mn going to guess the clock is gaining 10 minutes in about 6 hours. Pretty funny though. Wifey has been out the door 10-15 minutes early all week. I think I splained ot to her 3 times before she finally caught on. Big test is to see if she starts bitchin' about the clock being fast again. [popcorn]
:laugh:
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Dear God, you know I rarely ask you for anything. Ok, the occasional slow poke in front of me to turn so I can get to where the hell I'm going in a reasonable amount of time but that's about it. So just this one time could you PLEASE get me friggin power back today. Thank you! :angel:
God does read APS right? ;)
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Prolly should have left "hell" and "friggin out of the prayer. Estimated power back on time. Tuesday 6 PM.
[barf]
:lol:
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"I'n going to guess the clock is gaining 10 minutes in about 6 hours."
21600 seconds = 6 hours
600 seconds fast
21600 + 600 = 22200 seconds measured time.
(22200 seconds measured / 21600 actual seconds) X 60 = ~61.666 Hz.
Most devices should tolerate that kind of difference.
Must be the "666" screwing things up for you.
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Would you believe, the parameter for the error code is +/- 1.5 ;/
just the way my lucj has been going. Just traded in 40,000 bonus points on my CC for $400 worth of gas cards, Thought I'd get a month or so out of them for the truck. I'm down to $150 left buying gas for the gen. They will run out before Sept 6. No way to recover this either. Total loss. [barf]
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On the plus side, that's $400 you didn't have to actually spend out of your regular budget... At least you had that extra $400 instead of trying to squeeze it out of your regular budget.
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yes, I know, but I can still be pissed about it. I catch a break on gas for a change and it's snatched right away from me. Any idea how long it takes to accumulate 40,000 bonus points? :mad:
:lol:
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FYI, they seem to think if I remove all the inductive loads and then load it with about 1000W of resistive load it might work. I spose I should test this. the other option is to buy a Honda "Inverter Technology" generator as it is supposed to put out very clean power. 1000W would be just right for ther boilr only. $799. I only paid $500 for the 5000w coleman. :facepalm:
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yes, I know, but I can still be pissed about it. I catch a break on gas for a change and it's snatched right away from me. Any idea how long it takes to accumulate 40,000 bonus points? :mad:
:lol:
Oh, I know. Just trying to get you to look at it from the bright side.... :P
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Can you get to the governor? Slow the engine down slightly and the frequency will drop. (it'll last longer too) Of course it helps to have a frequency counter :facepalm: Iif you have a Kill-a-watt, it will do it.
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Oh, I know. Just trying to get you to look at it from the bright side.... :P
Bright side? :P
:lol:
I laugh as i sit here eating my 8 yo mre M&Ms thinking they taste ok but then again maybe a little odd. =D
i don't know how you poor bastards that had to eat those things actually ate those things. I'm beginning to understand the hot sauce story. Could you guys send me hot sauce, twizzlers and cigars please?
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Can you get to the governor? Slow the engine down slightly and the frequency will drop. (it'll last longer too) Of course it helps to have a frequency counter :facepalm: Iif you have a Kill-a-watt, it will do it.
I'll fiddle with the thing tomorrow and see if I cant get it to work.
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Put a UPS between the gen and the unit. This should clean up the wave and let it run.
jim
After I got a gen hooked up here my ups would just stay on battery. Something about the power it did not like.
Not sure what it was because the voltage was good. I've seen mine correct a 100 volt brown out without switching to battery.
FWI its an old best ferups 1.2kw I believe.
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What's a UPS?
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well, we're finding that the plug in digital clock gains time now. Resulting assumption is the gen frequency is higher than 60, Doesn't seem to affect anything else. I'm most worried about smoking the well pump but it seems to be working just fine.
I was just going to suggest finding the loudest-humming old analog clock at the flea market or Goodwill store, syncing it with your watch, and waiting an hour to see how much difference there is.
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Electrical Nirvana has been achieved. After sleeping on it I woke up realizing I have this electric griddle which turns out to draw 1600 watts. So I unplugged all the motor circuits, plugged in the griddle and like magic the boiler fired and stayed running. So I was right, there IS a little magic box that fixes things, it's just in the shape of a griddle. Bonus, you can cook on it too. Two birds one stone. :cool:
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Electrical Nirvana has been achieved. After sleeping on it I woke up realizing I have this electric griddle which turns out to draw 1600 watts. So I unplugged all the motor circuits, plugged in the griddle and like magic the boiler fired and stayed running. So I was right, there IS a little magic box that fixes things, it's just in the shape of a griddle. Bonus, you can cook on it too. Two birds one stone. :cool:
Didn't I mention a waffle iron 20+ posts ago? I thought I did...
What happens when you unplug it [the griddle]? Or it reaches full temperature and cycles off? Does the boiler keep working?
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Why yes you did but when I was reading that and the previous about the inductive load I got wiring it in series stuck in my head and I wasn't gonna be trying that. Thankfully. lol
I fergitted that to put a waffle iron in parallel with the generator you have to,,,plug it in. :facepalm:
Just because the internet says my IQ is 131 that doesn't mean I can't be stupid when I want to. :laugh:
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I was just going to suggest finding the loudest-humming old analog clock at the flea market or Goodwill store, syncing it with your watch, and waiting an hour to see how much difference there is.
Did that already. See post 31.
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What's a UPS?
Uninterruptable Power Supply -- it's a computer thingie for people who don't like to lose data when the power grid crashes. (Like in a hurricane.)
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ah, thanks!
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What's a UPS?
Uninterruptable Power Supply -- it's a computer thingie for people who don't like to lose data when the power grid crashes. (Like in a hurricane.)
And sometimes they are delivered to your door in large brown trucks.
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Somehow I knew there was a connection there. =D
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So is the waffle iron just slowing down the genset enough under its relatively heavy 1100W load to bring the frequency down juuuust enough, or is it somehow filtering out the odd-harmonic square-wave hash? (The waffle iron being a mostly resistive load, I find that hard to believe.)
With whatever small inductance the waffle iron may have, since it's in parallel, it would ignore the high harmonic frequencies and act as a high-pass filter and let any high-order harmonics through to the boiler. Which means it wasn't the harmonics screwing up the boiler's frequency-sensing circuits.
Terry, 230RN
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If the generator is the kind where the speed of the motor determines the frequency of the wave, then it must be a sine wave, right?
How does one generate a square wave with a rotating coil in a magnetic field?
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"If the generator is the kind where the speed of the motor determines the frequency of the wave, then it must be a sine wave, right?"
Agreed. Good point. (I think you mean "shaft speed" there instead of "speed of the motor", though.)
I've gotta think about that some more.
I believe even pretty high-powered generator sets nowadays are inverter outputs, with the active solid-state switches being high-powered Silicon-Controlled Rectifiers (SCRs). What frequency the generator actually produces doesn't matter with an inverter. I would bet that the actual generators nowadays are really alternators like a car's, where the frequency (due to rotational speed) doesn't matter much because it is then rectified and fed into a 110V (or whatever) 60hz (or whatever) inverter. Yours is a good point, and I don't know offhand how much frequency in an inverter would be affected by load. The SCR switching could be controlled with a crystal oscillator, but then you wouldn't have the frequency problem that 280plus is having in the first place.
I know they use SCRs in some pretty high-powered ultrasonic and induction heating systems, like in the many-kilowatt range.
I believe you can generate a pretty close sine wave with a square-wave input (or better, a triangle-wave input), but you need some pretty good pulse-modulation techniques to do it. Maybe they've gotten that far in consumer-type gensets.
On the other hand, you could get a fairly good basic sine wave of a specific frequency out of an alternator regardless of the rotational speed by modulating the rotor itself with an input sine wave of that specific frequency. The alternator then acts as an amplifier, rather than a generator. (Input power in this case is mechanical, rather than electrical, as in a conventional tube or transistor amplifier --there would be no "B+" or "Vcc.")
I actually put some of the above in my post, but deleted it.
See, I figured by now a "real" techie knowledgeable in actual and practical genset technology would enter the stage and have "real" answers, but noooo.... So I can theorize all I want, I guess.
Terry, 230RN
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Of course, none of this answers the obvious question; why the hell does a boiler care about the frequency of the supply? It's a resistive heating element (or a gas valve and spark igniter) and a thermostat.
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A. My guess is it drags the gen down just enough to get the frequency right.
B. Fancy dancy new fangled boiler with all kinds of bells and whistles. One being it monitors AC frequency coming in and coughs up an error code if it is out by over 1.5 cycle. Calcs by ML say gen was producing ~61.666 which would be a hair too high.
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Of course, none of this answers the obvious question; why the hell does a boiler care about the frequency of the supply? It's a resistive heating element (or a gas valve and spark igniter) and a thermostat.
Because some idiot figured out that it could monitor the frequency without any extra cost -- and when you monitor for an error you have to handle it.
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280, by and large for really big loads SCR's (and their larger brothers, thyristors) have been replaced with IGBT's. Which can handle LARGE loads. I've seen palm sized ones that can do 3000V and switch 1800A.
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^^^translation pleeeez... =D
FYI, power came on at midnight. Figures, Filled the tank on the gen to the brim before going to bed at 10. Now to get it back out of there and into my TRUCK!! dammit. lol...
It's been described to me as a CYA feature by the factory to prevent premature failure of the very expensive control module. As long as I can McGyver my way around it when I have to, it's cool.
As far as the other questions. I did not turn the griddle off and see if it tripped the boiler. I did hook the waffle iron up because it draws smaller watts (gas) and found it would still cycle off even if set all the way up. So during the time the boiler was using to make hot water it DID (the waffle iron) cycle off and the boiler did not hiccup. Now, it's entirely possible however that the boiler had completed it's cycle and had gone off before the waffle iron. This MAY mean that it might have tripped on the next startup as it went through its pre-cycle checkout stage but I had shut it off as soon as we had the hot water up, so I don't know. I don't know if it momentarily looks at frequency on startup or it monitors continuously. I guess I'll have to call them and ask. I wanted to relay the good griddle news to them anyways.
Anyhoo, thanks for all the help and suggestions. Now please turn your atention to the flogging of Fistful for causing the whole problem in the first place. =|
Feel free to wet your lashes first if you feel the need. ;)
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280, by and large for really big loads SCR's (and their larger brothers, thyristors) have been replaced with IGBT's. Which can handle LARGE loads. I've seen palm sized ones that can do 3000V and switch 1800A.
Ahh, power electronics... where the heavy lifting takes place... =D
Those are all three terminal, controlled, semiconductor devices. Like controllable diodes (SCRs, thyristors) or transistors (IGBTs), just capable of handling HIGH power. [ar15]
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Ahh, power electronics... where the heavy lifting takes place... =D
Those are all three terminal, controlled, semiconductor devices. Like controllable diodes (SCRs, thyristors) or transistors (IGBTs), just capable of handling HIGH power. [ar15]
Yup, and unlike thyristors, in large applications, they don't need a soft turn on to prevent blowing them up before the entire avalanche is setup, and they switch faster (due to their being array devices). I personally love them.
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^ My technology is limited to relays and Hg-filled thyratrons. Oh, the occasional SCR.
KD5NRH asked the question:
Of course, none of this answers the obvious question; why the hell does a boiler care about the frequency of the supply?
That's been running through my mind, too, and the only answer I can come up with is "If there's a bell, let's blow it, and if there's a whistle, let's ring it." Or to force those without waffle irons to buy the company's accompanying line conditioner.
The most expensive phrase you will ever hear is, "Why not go with the latest technology?"
Why.
Not.
Indeed.
There been talk recently of relaxing the power-line frequency standards --I forgot where I read it, but it's been on the net, so it must be true. So, the question arises: "Hey, Mr. Boilermaker, with your super-sensitive control modules inccorporating the latest and greatest frequency-sensing-technology, what happens if your latest-and-greatest-loaded-with-whistles-and-bells freakin' boiler is installed in an area where the line frequency is <B1-flat or >B1-natural. Hey? what about that, Mr. Boilermaker?"
They recently installed a microchip-controlled air conditioner in my place with, of all things, a remote control. I now have five remote controls sitting on the endtable by my couch. Way to lose weight, Terry! (But only in my button-pushing fingers.) Now if I could find a remote-controlled coffeemaker that would remote-controlledly (izzat a word?) extend an arm to my coffecup to fill it remote-controlledly I'd be in the sixth level of Nirvana.
Hm. Hey, why not use the latest-and-greatest word?
Terry, 230RN
REF:
http://www.phy.mtu.edu/~suits/notefreqs.html
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It's been described to me as a CYA feature by the factory to prevent premature failure of the very expensive control module.
Uh, it needs the same thing your waffle iron has; a mechanical thermostat. Costs about $8-15, doesn't give a rat's ass what the line frequency (or voltage, for that matter) is.
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Oh, don't think "OK, how do I get around all the BS and make the thing work anyways without blowing myself up or burning the house down?" hasn't crossed my mind. ;)
And yes, it can be done. =D
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QST: General call:
Harbor freight has those little generators for $89.99 on a coupon sale again. Coupons are available in the American Rifleman pp 20-21, September issue, for your convenience.
No need to clip the coupons. Just bring that issue in and they can scan the coupon right from the magazine without cutting up the pages.
(https://armedpolitesociety.com/proxy.php?request=http%3A%2F%2Fwww.harborfreight.com%2Fmedia%2Fcatalog%2Fproduct%2Fcache%2F1%2Fsmall_image%2F160x%2F9df78eab33525d08d6e5fb8d27136e95%2Fi%2Fm%2Fimage_11382.jpg&hash=74e613d1ff50f43a35b98c5c6fa8948115b9ab24)
DE TERRY 230RN WDØAAA
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Harmonics:
I picked up a 400 Watt inverter for $19.95 yesterday and stuck it on a fully charged battery with a known 400W resistive load (small emergency hot plate) on the inverter.
I have two meters that measure frequency. On one, the frequency was 59.87 Hz. On the other, it was 179.6 Hz. Interesting, because 179.6 is exactly the third harmonic of 59.87 Hz. So it must be putting out a square-ish wave with at least the first odd harmonic reduced and one meter is a little more sensitive to harmonics than the other. The blurb on the box says, "Modified sine wave for up to 85% efficiency."
One meter reads RMS voltage directly by sampling the waveform. The other reads (without saying so ) average voltage, and I stuck a little analog meter which inherently measures average, and they all read about 105 Volts on the output with that 400 Watt load --which implies that it is fairly close to a sine wave output.
For those having any interest.
Terry, 230RN
REF:
Chicago Electric Model 66814 from Harbor Freight. $19.95 with coupon.