I don't ever recall any brownouts, but we do have what is politely referred to as 'direct load shedding' ie. they just cease supplying power to an area/district. This is typically during the afternoon of an extremely hot day, suggesting that air conditioning is collectively pushing the generators to their limit. At the control room this would be first noted as a persistent unintended voltage drop despite firing up more generating capacity. So rather than damage, possibly irreparably as you point out, equipment the line is dropped completely from some region.
How on earth can anything break with not enough power? Things break when you give them too much. No motor or otherwise would get damaged from insufficient power.
And unless you live in deepest Peru, how can you have a lack of power? You do live in the modern world in a 1st world country right?
Mike Hewson wrote:
{ It's worthwhile recalling that voltage is the chosen measure for 'electromotive force' or EMF and that something has to push the generators to rotate against resistance from the circuit(s) it is attached too. Often superheated steam is used in turbines. Matching generation to load requires continual attention. }
Since the national grid connects thousands of power stations in parallel, they even out all by themselves.
Mike Hewson wrote:
The quoted numerology
"Numerology is the pseudoscientific belief in a divine or mystical relationship between a number and one or more coinciding events." Is that the word you meant to use there?
Mike Hewson wrote:
of supplied voltage for alternating currents can depend upon which aspect of the cyclic current that is being referred to. If power into a resistive load is the measure then the RMS or 'root mean square' of a sine wave is used, that being about 0.7071 of the peak voltage excursion. Hence if one rectifies 240V AC ( RMS ) supply then you will get about 340 V DC ( ie. 240/340 ~ 0.71 ) because +/- 340V are the extremes. For the RMS value between phases I'd have to do the math on the effective sine wave which is the difference of two sines, one offset by 120o from the other .... but you get the idea.
{ Ideal inductors and capacitors do not take a nett amount from the circuit they are in. Nothing is ideal. Indeed your fluorescent lamp would not illuminate if there was no resistive aspect. }.
I'll tell you what is nowhere near ideal. Smart meters. Which is why there will never be one installed in my house. They can read over by a factor of five(!) if you (ironically) use an energy saving device such as an LED lightbulb.
Mike Hewson wrote:
( edit ) ... as for plumes of smoke, the issue is frequently the start-up current to a compressor when the voltage is insufficient. So instead of some component rotating and expending mechanical power, the device's electric motor just sits there absorbing current resistively .... and I2R rules the day.
Never heard of such a thing. If the voltage is lower, it just doesn't have the power to do anything, movement, heat, or otherwise. P=V2/R, so half the voltage, a quarter of the power in the same coils. It won't magically draw more current.
If this page takes an hour to load, reduce posts per page to 20 in your settings, then the tinpot 486 Einstein uses can handle it.
How on earth can anything break with not enough power? Things break when you give them too much. No motor or otherwise would get damaged from insufficient power.
[...]
Never heard of such a thing. If the voltage is lower, it just doesn't have the power to do anything, movement, heat, or otherwise. P=V2/R, so half the voltage, a quarter of the power in the same coils. It won't magically draw more current.
voltage is not power. P = I*V. "not enough power" is not the problem, it's not enough voltage. they clearly said "voltage drop" not "power drop". they are not the same thing.
devices require power to run. if voltage drops, they pull more current to compensate. if voltage drops too low, current can reach a point to definitely damage something.
passive/resistive loads like a kettle or heater wont be damaged, and would operate at reduced power, but active constant power loads (which is what PCs and other electronics are, and what is actually being discussed) can be damaged by the current increase scenario I described.
Does anyone know why here in the USA we commonly speak of 220V, when in fact on the typical 2-phase layout it is just the sum of the two phases, which are quite commonly referred to as 120V, so the corresponding reference "ought" to be 240V?
I know I could run 2,400w through the standard outlets
Nope. Not if the rules are of any interest to you. You could look up what applies in your specific case, but as a generalization authorized load is 80% of the breaker value, not 100%.
Of course if you are talking about what you might get away with for a while, as seems the theme of some comments here, that is a different matter.
You are correct- that was an oversight in what I wrote. I would not feel comfortable to run 2,400w consistently through one of these lines, or even come close, in a school setting. Maybe some people would, I am not one of them. That is why we went with 208v because I didn't want to ever worry about approaching a high enough load that I would ever have to be concerned.
Yup. The voltage vs current curve is typically non-linear with active devices, or if you like resistance ( impedance to be exact ie. there's a phase lead/lag ) is a function of current or voltage.
I forgot to mention that, where I live, during hot periods with high winds load is shed in some areas to avoid sparks from colliding overhead slack wires creating bushfires ( eg. 2009 Victorian wildfire ). We use a small ~ 3.6 KVA 240 V AC generator for minimal house needs on such occasions, so that's 15 amps max. The key is to have that emergency supply and devices on a circuit quite separate from the incoming power line, as when that comes back on you can't have the home generator competing - out of phase - with the one at the power station !
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
passive/resistive loads like a kettle or heater wont be damaged, and would operate at reduced power, but active constant power loads (which is what PCs and other electronics are, and what is actually being discussed) can be damaged by the current increase scenario I described.
That would have to be the most terrible design ever for it to try to continue running outside its own limits. Would your PC power supply run at 1V AC, and try to draw 1000 amps to give out a kW? At some point it needs to cut out. That point has been set incorrectly if it can be damaged by low voltage.
If this page takes an hour to load, reduce posts per page to 20 in your settings, then the tinpot 486 Einstein uses can handle it.
Does anyone know why here in the USA we commonly speak of 220V, when in fact on the typical 2-phase layout it is just the sum of the two phases, which are quite commonly referred to as 120V, so the corresponding reference "ought" to be 240V?
this can be summed up in one word. colloquialism.
I thought it was actually 110-0-110? Voltages seem to change over time due to fashion or matching other countries. The UK went from 250V to 240V to 230V. The EU stayed at 220V. I get 240V-256V depending on the mood of the substation. I had to fit my lighting circuit to my PC UPS to stop LED bulbs dying quickly.
If this page takes an hour to load, reduce posts per page to 20 in your settings, then the tinpot 486 Einstein uses can handle it.
I know I could run 2,400w through the standard outlets
Nope. Not if the rules are of any interest to you. You could look up what applies in your specific case, but as a generalization authorized load is 80% of the breaker value, not 100%.
Of course if you are talking about what you might get away with for a while, as seems the theme of some comments here, that is a different matter.
You are correct- that was an oversight in what I wrote. I would not feel comfortable to run 2,400w consistently through one of these lines, or even come close, in a school setting. Maybe some people would, I am not one of them. That is why we went with 208v because I didn't want to ever worry about approaching a high enough load that I would ever have to be concerned.
So when I use my tumble dryer at the full 13 amps of my outlet, I'm risking an explosion or fire? I don't think so. If the outlet is x amps, you can take x amps. All the time.
In fact at the school I worked at, a PE teacher managed to run two tumble dryers and two washing machines all off one outlet. For a while. A few months later she gave me the melted power strip and asked for a replacement. I gave her two, now she puts a dryer and a washer on each of two outlets, so not so much over the limit. I guess the fuse in the power strip wasn't up to its job.
My car can go 120mph. I can drive it like that for hours, it doesn't overheat. My GPU will do 8 teraflops, it doesn't break if I run it flat out 24/7.
Just wait till someone doesn't notice the outlet is 208V and plugs a 120V device into it. Gotta love the UK, one voltage and one voltage only.
If this page takes an hour to load, reduce posts per page to 20 in your settings, then the tinpot 486 Einstein uses can handle it.
Yup. The voltage vs current curve is typically non-linear with active devices, or if you like resistance ( impedance to be exact ie. there's a phase lead/lag ) is a function of current or voltage.
That'll be why my 8 amp AC tends to make 13A wires hot.
Mike Hewson wrote:
I forgot to mention that, where I live,
From the below nonsense I'm guessing California, they really need to get their act together with power distribution.
Mike Hewson wrote:
during hot periods with high winds load is shed in some areas to avoid sparks from colliding overhead slack wires creating bushfires ( eg. 2009 Victorian wildfire ).
I have a brilliant idea! They could replace the wires! You have wires that can collide?!
Mike Hewson wrote:
We use a small ~ 3.6 KVA 240 V AC generator for minimal house needs on such occasions, so that's 15 amps max. The key is to have that emergency supply and devices on a circuit quite separate from the incoming power line, as when that comes back on you can't have the home generator competing - out of phase - with the one at the power station !
Totally unnecessary, do what I did with my own solar setup. Get some relays that will switch 30 amps and have a 240V input coil. They disconnect the generator (or in my case the inverter) when mains power exists. Anyway, your generator would be shoved into phase, just like happens between competing power stations on the grid.
If this page takes an hour to load, reduce posts per page to 20 in your settings, then the tinpot 486 Einstein uses can handle it.
Mike Hewson wrote:I don't
)
How on earth can anything break with not enough power? Things break when you give them too much. No motor or otherwise would get damaged from insufficient power.
And unless you live in deepest Peru, how can you have a lack of power? You do live in the modern world in a 1st world country right?
Since the national grid connects thousands of power stations in parallel, they even out all by themselves.
"Numerology is the pseudoscientific belief in a divine or mystical relationship between a number and one or more coinciding events." Is that the word you meant to use there?
I'll tell you what is nowhere near ideal. Smart meters. Which is why there will never be one installed in my house. They can read over by a factor of five(!) if you (ironically) use an energy saving device such as an LED lightbulb.
Never heard of such a thing. If the voltage is lower, it just doesn't have the power to do anything, movement, heat, or otherwise. P=V2/R, so half the voltage, a quarter of the power in the same coils. It won't magically draw more current.
If this page takes an hour to load, reduce posts per page to 20 in your settings, then the tinpot 486 Einstein uses can handle it.
Peter Hucker wrote:How on
)
voltage is not power. P = I*V. "not enough power" is not the problem, it's not enough voltage. they clearly said "voltage drop" not "power drop". they are not the same thing.
devices require power to run. if voltage drops, they pull more current to compensate. if voltage drops too low, current can reach a point to definitely damage something.
passive/resistive loads like a kettle or heater wont be damaged, and would operate at reduced power, but active constant power loads (which is what PCs and other electronics are, and what is actually being discussed) can be damaged by the current increase scenario I described.
_________________________________________________________________________
archae86 wrote: Does anyone
)
this can be summed up in one word. colloquialism.
_________________________________________________________________________
archae86 wrote: Boca Raton
)
You are correct- that was an oversight in what I wrote. I would not feel comfortable to run 2,400w consistently through one of these lines, or even come close, in a school setting. Maybe some people would, I am not one of them. That is why we went with 208v because I didn't want to ever worry about approaching a high enough load that I would ever have to be concerned.
Yup. The voltage vs current
)
Yup. The voltage vs current curve is typically non-linear with active devices, or if you like resistance ( impedance to be exact ie. there's a phase lead/lag ) is a function of current or voltage.
I forgot to mention that, where I live, during hot periods with high winds load is shed in some areas to avoid sparks from colliding overhead slack wires creating bushfires ( eg. 2009 Victorian wildfire ). We use a small ~ 3.6 KVA 240 V AC generator for minimal house needs on such occasions, so that's 15 amps max. The key is to have that emergency supply and devices on a circuit quite separate from the incoming power line, as when that comes back on you can't have the home generator competing - out of phase - with the one at the power station !
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
Ian&Steve C.
)
That would have to be the most terrible design ever for it to try to continue running outside its own limits. Would your PC power supply run at 1V AC, and try to draw 1000 amps to give out a kW? At some point it needs to cut out. That point has been set incorrectly if it can be damaged by low voltage.
If this page takes an hour to load, reduce posts per page to 20 in your settings, then the tinpot 486 Einstein uses can handle it.
Ian&Steve C. wrote: archae86
)
I thought it was actually 110-0-110? Voltages seem to change over time due to fashion or matching other countries. The UK went from 250V to 240V to 230V. The EU stayed at 220V. I get 240V-256V depending on the mood of the substation. I had to fit my lighting circuit to my PC UPS to stop LED bulbs dying quickly.
If this page takes an hour to load, reduce posts per page to 20 in your settings, then the tinpot 486 Einstein uses can handle it.
Boca Raton Community HS
)
So when I use my tumble dryer at the full 13 amps of my outlet, I'm risking an explosion or fire? I don't think so. If the outlet is x amps, you can take x amps. All the time.
In fact at the school I worked at, a PE teacher managed to run two tumble dryers and two washing machines all off one outlet. For a while. A few months later she gave me the melted power strip and asked for a replacement. I gave her two, now she puts a dryer and a washer on each of two outlets, so not so much over the limit. I guess the fuse in the power strip wasn't up to its job.
My car can go 120mph. I can drive it like that for hours, it doesn't overheat. My GPU will do 8 teraflops, it doesn't break if I run it flat out 24/7.
Just wait till someone doesn't notice the outlet is 208V and plugs a 120V device into it. Gotta love the UK, one voltage and one voltage only.
If this page takes an hour to load, reduce posts per page to 20 in your settings, then the tinpot 486 Einstein uses can handle it.
Mike Hewson wrote:Yup. The
)
That'll be why my 8 amp AC tends to make 13A wires hot.
From the below nonsense I'm guessing California, they really need to get their act together with power distribution.
I have a brilliant idea! They could replace the wires! You have wires that can collide?!
Totally unnecessary, do what I did with my own solar setup. Get some relays that will switch 30 amps and have a 240V input coil. They disconnect the generator (or in my case the inverter) when mains power exists. Anyway, your generator would be shoved into phase, just like happens between competing power stations on the grid.
If this page takes an hour to load, reduce posts per page to 20 in your settings, then the tinpot 486 Einstein uses can handle it.
Peter Hucker wrote: Just
)
They can't do that since 208V/240V receptacles have very different plug geometries and sizes compared to standard 120V plugs.
NEMA plug chart
https://upload.wikimedia.org/wikipedia/commons/thumb/0/0d/NEMA_simplified_pins.svg/350px-NEMA_simplified_pins.svg.png