Brown Outs?greenspun.com : LUSENET : TimeBomb 2000 (Y2000) : One Thread
If nothing else, Y2k has made me learn about many different things. I have become the perfect bore at any cocktail party. I know a little about: Fiat money, stock market, food distribution, desease, rail roads, shipping, fuel, (fossil and nuke) mob psychology, religion, firearms, food and water storage and on and on. I have glibly pronounced that we may experience if not black outs, brown outs. I just realized that I don't know what a brown out is.
Is is a constant delivery of low power? Is it full power with intermittent periods of low power? Do industrial size electric motors shut down or just go slower? Will an elevator ride become a crapshoot? Do surge protectors just protect against spikes of excess power, or do they trip if there is low power? What the hell is "Dirty Power"? How could that effect electric motors and computers?
I really would like to know. Might help me become even a bigger bore at my next party if I get invited again.
Bill in South Carolina
-- Bill Solorzano (email@example.com), January 17, 1999
- Temporary (minutes to hours) period of varying undervoltages. This can seriously harm many kinds of electrical motors and other devices. The "dirtyness" refers to its variability in voltage and phase.
-- RD. ->H (firstname.lastname@example.org), January 17, 1999.
a: yes b: yes c: yes d: yes! e: yes, no
-- plain ol' joe (email@example.com), January 17, 1999.
But think how well you will do at the really big "party" coming up. People will find you a fountain of knowledge.
"Bill, why am I so hungry?"
"Bill, why is it so dark?"
"Bill, why is my bank closed?"
"Bill, why do I have these weeping bumps all over me?"
"Bill, why are those people turning over cars and setting them ablaze?"
"BIll, what end do the bullets come out of?"
You are gonna be one very popular fellow!
"Bill, do you have any extra rice?"
-- Uncle Deedah (firstname.lastname@example.org), January 17, 1999.
The most common "brownouts" are when one side of a three phase line goes open. The other two are still operating but will supply a reduced voltage. Motors that run on three phase will soon burn out. Homes that receive a two phase breakdown from their pole transformer will also receive a lower voltage and any refridgerator, washer, air conditioners will suffer similar fates.
The first thing to do when you see your lightbulbs burning dimmer than normal is to disconnect all electrical devices (including t.v.'s, etc.) from their power sources. You can keep the lights on and use electric heaters or cooking devices. The fans in these heaters would suffer so their leads should be cut but the heating elements would still produce (a lower) heat. Use common sense and play safe when modifying anything like this.
In any event, this type of brownout usually results from physical damage to the transmission lines. I do not believe it will be something to worry about regarding y2k computer problems. Those will certainly deal the same blow to all three phases, not just one.
Dirty power or spikes and hits come from many sources but in the y2k senario, it will likely be from power going up and down in other areas and thereby affecting you. When an area looses power, it is gone instantly. To restore it takes much longer. That motor that was running your refrigerator has a start coil which takes perhaps three times the current to get it moving again. After it is running it switches off and much less current keeps it moving. When one tries to start *all* the refrigerator motors in the city at the same time, they just won't. Each small section of any community has to be turned on seperately with the full capacity of the much larger power system at its disposal for the few minutes of starting everything in that area. *All* devices btw use an extra surge of current at start up; even the actual lines that carry the switched on juice have a surge factor. That's why most light bulbs burn out on turn on. These surges, if significant, will suck the power from surrounding areas that are receiving normal power.
-- Floyd Baker (email@example.com), January 17, 1999.
I'm not as proficient with electronics as I wish that I was right now. One thing to consider about a generator, is how clean the output is. The first one my dad bought had so many spikes in the wave that the UPS didn't even recognize that it had power. Fortunately, they now have one that will safely run the computers at their office. I've read a lot about power plants going back to using manual controls if the automated systems failed. Couldn't this cause problems with the quality as well as the quantity of power they produce? If Mr. Baker or anyone with knowlege in this area could answer that question, I'd appreciate it.
-- d (firstname.lastname@example.org), January 17, 1999.
Dirty electricty. My mother recently had an experience where the grounding wire to her home broke. She called me and I checked both sides of the 220 with a volt-ohm meter. One side was 60 vac, the other was around 145 vac. She lost her vcr, microwave, cordless phone and a couple of clocks. Dirty electricty at a location near you soon !
-- reed moore (email@example.com), January 17, 1999.
Another related thing that is being discussed is the possibility of power rationing. If you haven't checked out Rick Cowles site, you may find it interesting. The url is http://www.euy2k.com and it is regarded as one of the best on the net, perhaps the best on the electric utilities topic. He recently gave an interview in which he also discussed the idea of who gets power if there are shortages. It turns out that emergency services are the last to get cut off, and next (surprisingly to me) are residential customers.
-- Rob Michaels (firstname.lastname@example.org), January 17, 1999.
Well.. ahem.. I know a *little* bit about 'lectricity...
Bill, your first two questions are just two ways of asking the same thing; it depends on your definition of "intermittent periods." Industrial motors will slow down and overheat. The overheating can trip thermal protection causing them to shutdown. (True for elevators as well) Surge protectors will not necessarily trip due to low power conditions. "Dirty power" is not really a good techical term, as it encompasses anything other than in-spec 60 Hz sinusoidal AC. Such as, overvoltage, undervoltage, overfrequency, underfrequency, surges, sags, spikes, noise.
Floyd's example isn't really a brownout, it's a fault. Brownouts are caused by overload or undersupply, and are reflected on all phases. Also, underfrequency effects can accompany brownouts. (Overloads cause generators to slow down, but beyond a certain point, they are removed from the grid, because an unsynchronized generator *draws* power from the grid)
(Now you know why we only speak of these things in low tones in the corner of the room.)
-- Elbow Grease (Elbow_Grease@AutoShop.com), January 17, 1999.