Why no Residential Fridges?

[sailorchic34]

Here's just one link that supports my stance.

From Speed Of Electrons

Electrons can have a wide range of speeds. A slow case: we know that electrons move when there is a current flow in a wire, but the speed at which the electrons themselves move in the wire - the so-called electron drift velocity - surprises most people. For example, for a copper wire of radius 1 mm carrying a steady current of 10 Amps, the drift velocity is only about 0.024 cm/sec! On the fast side: the Bohr model of the hydrogen atom has the (bound) electron zipping around the nucleus at about 2 million meters/sec.

And on the very fast side, some examples are: beta particles, which are emitted by some radioactive materials; and the innermost electrons of atoms of elements having large atomic number, such as Uranium. In these cases, the electrons are traveling at very nearly the speed of light. (about 300 million meters/sec). [from Classroom Resources | Argonne National Laboratory ] Although the drift velocity in a wire is small, the thermal velocity of the electrons tends to be quite large. Something of the order of 100,000 meters/sec.

So they are buzzing about at random at high speeds, with a small superimposed drift velocity caused by the electric field. Electric current is essentially a measure of how many charge carriers you can move through a given cross-section of conductor in a given amount of time. This will depend on the size of the cross section, the number of charge carriers, and their velocity. A current of 1 A corresponds to a transfer of 1 Coulomb of charge per second. An electron carries 1.6*10-19C so you need to move 6.3*10^18 electrons/sec.

Divide by the density of electrons in a copper wire (about 8.45*10^22 electrons/cm^3) and the cross section of the wire (for AWG 18 this is pi*(1.02mm/2)^2 or 0.008 cm^2) and you get 0.0093 cm/s.

[Scot McPherson]

This thread just needs to die


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[svlamorocha]

Originally Posted by Cadence

If it didn't put the /, per hr. it's my fault.

I guess the point being, HP and cc/cu. in. is BS. A 12V567A EMD locomotive engine/ GM LST engine is 6804 cu. inches, blown two cycle was rated at 900hp at 900 rpm. Now equate that to todays bogus claims of HP.

I take you do not believe that displacement has anything to do with power produced by a combustion engine. I believe it is very likely that the HP figures you think are bogus can in fact be explained by displacement, compression ratio, rpm, admission pressure and # of strokes.

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[belizesailor]

Geez...if I was a gun toting cruiser, I would shoot this badly beaten horse for you.

[StuM]

Originally Posted by sailorchic34

Stu, Please post a link to a paper or electrical text that defines an amp as Speed of the current.

That's hard to do since it is so fundamental that it generally needs no definition:

Electric Current

"current is the rate at which charge flows past a point on a circuit."
...
Current is a rate quantity. There are several rate quantities in physics. For instance, velocity is a rate quantity - the rate at which an object changes its position.
....
In every case of a rate quantity, the mathematical equation involves some quantity over time.
...

The standard metric unit for current is the ampere. Ampere is often shortened to Amp and is abbreviated by the unit symbol A. "

So Amp is a measure of a current which is a "rate quantity'.
or Amp = measurement of a rate quantity. (1)


And what is a "rate quantity"?

Look at the definitions of "speed" above. In line with all of those definitions and examples:

Speed = the measurement of a "rate quantity" (2)

Ergo from (1) and (2): Amp = speed.

[StuM]

Originally Posted by belizesailor

Geez...if I was a gun toting cruiser, I would shoot this badly beaten horse for you.

Me for the last couple of days:



https://xkcd.com/386/




I think I'm done this time

[sailorchic34]

Originally Posted by StuM

So Amp is a measure of a current which is a "rate quantity'.
or Amp = measurement of a rate quantity. (1)


And what is a "rate quantity"?

Look at the definitions of "speed" above. In line with all of those definitions and examples:

Speed = the measurement of a "rate quantity" (2)

Ergo from (1) and (2): Amp = speed.

Ah, your mixing different rate quanititys. Current is a rate quanitity as is acceleration and power. But an ampere is not an acceleration or power.

From your link, but a bit further down:

One might then ask: How can there by a current on the order of 1 or 2 ampere in a circuit if the drift speed is only about 1 meter per hour? The answer is: there are many, many charge carriers moving at once throughout the whole length of the circuit. Current is the rate at which charge crosses a point on a circuit. A high current is the result of several coulombs of charge crossing over a cross section of a wire on a circuit. If the charge carriers are densely packed into the wire, then there does not have to be a high speed to have a high current. That is, the charge carriers do not have to travel a long distance in a second, there just has to be a lot of them passing through the cross section. Current does not have to do with how far charges move in a second but rather with how many charges pass through a cross section of wire on a circuit.

Red highlight be me. There you go, from you own example.

What is a charge carrier. In this case, electrons. Electrons carry the charge.

[StuM]

Originally Posted by sailorchic34

Current does not have to do with how far charges move in a second but rather with how many charges pass through a cross section of wire on a circuit.

Red highlight be me. There you go, from you own example.

What is a charge carrier. In this case, electrons. Electrons carry the charge.

Which is exactly what I have been saying all along. If you understood what you have just repeated, you would realise this.

It's the RATE at which electrical charges pass through a point/cross section of the conductor where RATE and SPEED are synonymous. (And electrical charges are Coulombs). It is not speed of motiion, it is speed of energy flow.

And the implications of your last sentence are the crux of it:
Yes, the "charge carrier" is electrons, but the charge carried is not.

The charge is energy. Electrons are mass. The electrons just sit there passing the electrical charge(energy) from one to the next at a very high speed . Like bucket carriers in a bucket chain.

So you cannot measure charge (Amp Hours or whatever) by counting electrons any more than you can measure gallons of water by counting the number of people in a bucket chain.

Neither the slight movement of the electrons not any slight movement of the bucket carriers affects the rate (aka speed) at which the electrical charge or water flows. It's purely down to how fast (at what speed) an electron/bucket carrier can pass a single charge/bucket to his neighbour and how many electrons/bucket chains are standing side by side.

See http://hyperphysics.phy-astr.gsu.edu...ic/elecur.html

[four winds]

Holy cow!

BTW, no single electron moves any further than the copper atom next to it.

Copper has a single electron in the outer shell, a covalent electron. That's what makes copper a good conductor. The single electron has a bond that is easy to nudge into the next atom. Which nudges the single electron there on to the next atom, and on and on.

For what it's worth.

Not that it matters.

Oh, and negative to positive, that's electron flow theory. And how the US Air Force teaches.

The US Navy teaches conventional flow theory, positive to negative.

This dialog reminds me of trying to talk to to some Navy tech's back in the day.

[newhaul]

Originally Posted by sailorchic34

It's really the only thing I came up with, because its quite easy to do a tiny bit of research on the web. I'm thinking I'm just about done here.. It's been fun though. I think we deserve an award for the biggest thread drift ever on Cruisers Forum.

Here here I second the motion all in favor signify by a show of hands and the words aye all opposed signify by stating nay.

[newhaul]

Originally Posted by four winds

Holy cow!

BTW, no single electron moves any further than the copper atom next to it.

Copper has a single electron in the outer shell, a covalent electron. That's what makes copper a good conductor. The single electron has a bond that is easy to nudge into the next atom. Which nudges the single electron there on to the next atom, and on and on.

For what it's worth.

Not that it matters.

Oh, and negative to positive, that's electron flow theory. And how the US Air Force teaches.

The US Navy teaches conventional flow theory, positive to negative.

This dialog reminds me of trying to talk to to some Navy tech's back in the day.

Hey I resemble that remark I were a navy tech nuke welder to be exact

[TeddyDiver]

An engineer and a humanist were arguing, which one won?

[four winds]

Originally Posted by newhaul

Hey I resemble that remark I were a navy tech nuke welder to be exact

Ha! Go Navy! Thanks for your service.

Damn good thing it doesn't matter if the arc flows from the weld to the tip, or from the tip to weld.

USAF, Electronic Countermeasures here.


What was this thread about again? Oh yeah, love my little 78 dollar dorm fridge. Shows 65 watts on the inverter when running, with 10 minutes per 60 minutes duty cycle.

No way, no how I will try to state current flow or usage figures for fear of a verbal flogging.

[newhaul]

Originally Posted by four winds

Ha! Go Navy! Thanks for your service.

Damn good thing it doesn't matter if the arc flows from the weld to the tip, or from the tip to weld.

USAF, Electronic Countermeasures here.


What was this thread about again? Oh yeah, love my little 78 dollar dorm fridge. Shows 65 watts on the inverter when running, with 10 minutes per 60 minutes duty cycle.

No way, no how I will try to state current flow or usage figures for fear of a verbal flogging.

thank you for yours
Actually it did matter lots when welding inconel flow was from positive to negative ( the torch was pos and pipe negative) I still prefer my 12 volt holding plats system 60 watts for 5 hours a day. So 300 watt-hours

[Wotname]

With all this talk about current flow and Amperes, I thought some of you might like to be reminded of the fundamental definition of Amperes.

The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 meter apart in vacuum, would produce between these conductors a force equal to 2 x 10-7 newton per meter of length.


There, that should tidy things up somewhat