What Is Your AC Line Voltage Coming In To Your Rig?

TSJMajesty said:
Well I'll be damned! Just did a quick experiment..., turned on all 4 electric stove burners and the A/C kicked on, and it dropped to 120.

So do the power companies purposely send us higher than 120, to account for usage?
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Real engineers jump in here, but isn’t the voltage really an average with ac current? “Average” is not technically correct, but point being its never a constant value is it?
 
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DallasGlenn2005 said:
Real engineers jump in here, but isn’t the voltage really an average with ac current? “Average” is not technically correct, but point being its never a constant value is it?
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There is a voltage range they shoot for, and variance around that. Just like literally everything else in the analog world, there's the paper specification, and then there is the reality of what you actually receive, which sometimes coincide exactly, but mosly only approximate the specification....
 
Yeah as current flow goes up, voltage drops. It's like executions in old prison movies when they fire up Ol' Sparky and the lights throughout the prison dim and flicker. The same thing happens on a larger scale across the wider supply system. When usage is really high, like during the heat of the day in the summer when everyone's air conditioners are running full blast, the voltage across the whole system will be pulled down lower. Inversely, in the middle of the night when usage is lower and voltage will typically be a bit higher. It fluctuates throughout the day. Power generators and regulators monitor things very closely and adjust the supply as needed to keep the voltage as stable as possible, but it's pretty much impossible to keep it exactly the same everywhere as usage is constantly changing.
 
DallasGlenn2005 said:
Real engineers jump in here, but isn’t the voltage really an average with ac current? “Average” is not technically correct, but point being its never a constant value is it?
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You are right. It is never constant. The instant voltage is a function of time, as the wave goes up and down through the positive and the negative crests. If you were fast enough to touch a 3000V line only during the micro-instant while it is zero, you would not get fried (a 60HZ AC goes to zero every 0.004 seconds, so that would be an infinitesimal part of that) :p

The Instant Voltage is:

V(t) = Vpeak sin(wt)

Where
  • Vpeak is the peak voltage (unit: volt),
  • w is the angular frequency (unit: radian per second)
  • t is the time (unit: seconds)

The "common" voltage that we are talking about is not the average, it is the RMS (root-mean-square). The AC RMS voltage is the equivalent to the DC voltage that produces the same heating effect for a given current. The RMS is lower than the peak value

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TSJMajesty said:
I'm just curious..., I've noticed in many rig pics, the AC voltage always seems to be higher than 120. Like I just saw one that was @ 125. Mine is always around 122.

Anyone know why that seems to be the norm?
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Is that all Edison could do for you?
You guys are running low :D
20210904_133753.jpg
Between 230.4V and 230.5V here
 
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Contrary to popular belief, the US does use a 240 Volt system. We just use a center tapped transformer to split it into two opposing phases and put some circuits on one phase and some on the other with a grounded neutral conductor between them. Some high current large appliances like stoves, ovens, air conditioners, clothes driers, etc. bridge both phases together and operate on 240 volts directly.
 
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Piing said:
Is that all Edison could do for you?
You guys are running low :D
View attachment 88094
Between 230.4V and 230.5V here
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Edison pushed for a DC based system, which was pretty limited in comparison to the further reaching AC system Tesla/Westinghouse pushed for. Crazy bastard supposedly used to electrocute animals using AC to show how dangerous it was and scare people away from it. He supposedly even killed an elephant once, though it's been debated if he actually had anything to do with it. His business practices were questionable to say the least.

Ironically, there's been a bit of a return to DC for very long distance transmission lines. They use extremely high voltages, often in the 300 to 400 thousand volts range, to minimize current flow and wire resistance losses.
 
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mr_fender said:
Contrary to popular belief, the US does use a 240 Volt system. We just use a center tapped transformer to split it into two opposing phases and put some circuits on one phase and some on the other with a grounded neutral conductor between them. Some high current large appliances like stoves, ovens, air conditioners, clothes driers, etc. bridge both phases together and operate on 240 volts directly.
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Yup. That's why I posted earlier that when I run my electric dryer at 220v my line voltage
drops upwards of 4 or 5 volts from 124-5 to 119-120.
 
mr_fender said:
Contrary to popular belief, the US does use a 240 Volt system. We just use a center tapped transformer to split it into two opposing phases and put some circuits on one phase and some on the other with a grounded neutral conductor between them. Some high current large appliances like stoves, ovens, air conditioners, clothes driers, etc. bridge both phases together and operate on 240 volts directly.
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Likewise, Europe uses a 3 Phase 380V system. Large appliances operate at 380V III.
 
Yeah, 3 phase is also used here in the US, but mostly for industrial applications or for feeding substations and really large buildings. That's why you'll usually see three separate wires on transmission lines, one for each phase.
 
mr_fender said:
Yeah, 3 phase is also used here in the US, but mostly for industrial applications or for feeding substations and really large buildings. That's why you'll usually see three separate wires on transmission lines, one for each phase.
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Yep. The really large transmission lines usually have multiples of 3 wires, and even the lower voltage poles along 2-lane roads carry the 3-phase up on top. If you look up, every so often you'll see a pole-mounted, step-down transformer, which drops the voltage down to 120, then sends a leg of each to residences. In newer areas, the transformers are surface-mount (those big green boxes), and the redidential lines are underground.
 
Well, my power is back up again, @ 128. I've been watching it on the Furman slowly rise the last few days, but tonight is the highest it's gotten. The weather temps are in the 60's, and have been for a few days, after being in the teens overnight, so maybe with less draw from electric heat overall, the voltage has risen.
Anyway, I called the power company again, and we'll see how long it takes them this time (last time they came out within an hour on a Sunday morning.)
 
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