Attached File

Lol, I think it wasn’t until well after the automobile was invented that they actually figured out which way the electrons moved.  

They didn’t have the technology to see it.

Wait until you learn that "electron flow" is not the basis of electrical conduction. In fact, electrons flow relatively little. Electromagnetic field "flow" is what's actually at play.

More appropriate to think about charge in terms of power, where the + is the energy flow source, & - is the destination.

You have to admit, it was kind of epic when he stole electricity from Zeus

Your teacher sucked. My high school chem teacher back in the day said ol Ben got it wrong, but we'll just use that +/- standard because that's how everyone thinks of voltage drops working. However, only recently did veritasium explain the fields and how electricity worked to power the toaster, even though I got an A in a semester of E&M in engineering physics in skrool.

Hole flow in semiconductors is another "reverse" concept.

I’m sensing a lot of NEGATIVITY here!

Yes it does....that's why you can pinch an extension cord to stop power to a saw while you change the blade....it saves you time from shutting it off.

electric theory is polar opposites between electrical engineers and physicists

always has been

just ignore the so called physicists and go on with life

oh and there is no such thing as electron flow, they don't actually move,  the whole thing is just a model so we can wrap our brains around  it and make stuff but electrons dont actually flow, they dont move at all. current is not electrons.

IIRC she is a chick not a guy

Ok, I'm awake.


I took one year of undergrad physics in college. I took several semesters of chemistry. I'm not an electrician, I'm a retired medical microbiologist (as opposed to other microbiologists).

I worked in a genetic research lab in college which was really cool.

Before moving to the microbiology department I rotated in the other departments in the lab. There are a lot of instruments involved in the testing which require maintenance and simple troubleshooting. Way back when cars were mechanical I did what I needed to keep my Volkswagen and '73 olds delta 88 alive, they had Chilton manuals back then so it was semi-fun. I could use a dwell meter and could adjust and change points and condenser, replace alternator, do the drum brakes, and various other routine and simple repairs.

None of this required extensive electrical understanding. But I'm comfortable with minor household electrical repairs.

So through all of this I managed to simply overlook Franklin's fuck up, which is addressed in every electrical book I have.

I thought I would dip my toe in the world of Arduino. This is great because most of this stuff is on the website. I'm still trying to understand how various components work and make little circuits on my little breadboard. It's fun and gives me something to do that doesn't involve going out in 95 degree weather. Most of my sources are geared to ages 10 and up .

What really chapped my ass is the various contradiction of the definition of anode and cathode. Well there is more like calling the place where the electrons come from the positive probe and vice versa. I have to accept it but I don't have to like it. And the deeper you go the more Ben Franklin's little screw up stands out.

But I'm going to build that little fucking car if it's the last thing I do, and it probably will be.

At least chemistry makes sense. I actually enjoyed all of the chemistries, although they were undergrad courses. I never took graduate courses, I assume it gets more challenging but I'm really old now so I'll never know.

Almost forgot, I dipped my toe in household repair because the so-called electrician recommended by my neighbors was a raging alcoholic and fucked up every simple thing I had him do. I went back and fixed each thing as they failed and if my neighbor ever recommends anyone again I will do the opposite.

And all of that makes perfect sense. What doesn't make sense is calling the anode the negative thing in some instances and the positive thing in others.

Or having to use terminology like "electric current" and "conventional current" because everyone wants to white knight Ben Franklin.

We have to pretend current is the movement of positive charge because of Franklins fee fees.


Notice how the post I'm quoting avoids that topic all together.

That was a good one.

That was in one of my books. I was going to post it but didn't want to emphasize I'm using books for children.

I have others but I quickly put them down in favor of " for ages 10 and up"

All cats are grey in the dark.  Words to live by.

At least you and the poster above understand the source of my rage.

But at least I know we went to the moon. And how lightbulbs work. And why boats float. And the various other topics I've read here.

I don't think Ben Franklin could ever be accused of putting pussy on a pedestal. He owned every coochie from Philly to Paris, rode them hard and put them away drunk and sopping.

Priority? Sure. Pedestal. Na. He wrecked more pussies than syphilis.

I knew exactly what this thread was going to be about from the title.

The energy that causes the electrons to flow does come out of the positive terminal though.

I remembered it because "cathode" has a "t" that looks like a plus sign and Ann (someone I knew) was a negative person.

And I still got the answer right. I would get out my physics book but it's falling apart, I actually have referred to it many times over the years. I'm afraid to get a current one to replace it, the new ones probably have trannies and Trump references in them.

Yeah, I'm to understand it flows on the surface of the wire. Except AC, they just jiggle or something.

I actually kind of understand that in a simple childlike way.

Yeah, but I don't do the "IT'S MA'AM" thing, I just ignore it.

Like I should ignore conventional theory.

I'm pretty sure there's someone at Boeing who curses me for some Model Node #1/#2 and Bus Parameter L_ENG/R_ENG mismatch.

I can't recall if I ever fixed that.  If I didn't, and they were really, really bothered by it, I suppose they could fix the transposition, themselves.  Though, I'd much rather they didn't; that's they'd internalize their rage; and, I'd get to read about it in a post on Arfcom.

and you don’t understand brevity

Well then, Zeus should have locked his fucking car doors.

Attached File

The only President of the United States who was never President of the United States...

thats not a mnemonic.  violet loves massaging her vagina until she explodes is a mnemonic.

Welp, I'm off to scoop up some mosquito larvae for my little fishies.

Some of the replies were pretty helpful, thanks to all that replied.

A couple of my little fishies. They look totally different from when I got them, the male was white, I named him Casper, and the female only had small spots, her name is Confetti.

I have them where I can see them when I'm in the den and I'm mostly in the den. They give me hours of entertainment and happiness watching their antics. I tried giving them little tiny tadpoles to eat but they just spit them out all dead and in pieces. I have a big one in Casper's tank for him to flare at and chase, he's too slow to kill the big ones but looking for it gives him something to do and a reason to live.

Attached File


Attached File

Wtf

Induction is the ability of one conductor to induce a voltage (and subsequent current) into another conductor. The (3) things needed for induction to occur are:
-conductor
-magnetic field
-relative motion between to above (2)

In order to understand how induction works & affects in an AC circuit, we need to understand that (2) things happen when current flows through a conductor:
-heat is produced, due to the friction created by the electrons traveling from valence ring to valence ring of the atoms
-a magnetic field is radiated outward in a cylindrical shape/direction

Both of the above (2) are proportional to the amount of current flowing through said conductor. Assuming any given conductor size, the heat will increase due to more electrons flowing (increase in friction) & the mag field will increase.

This magnetic field is created similarly to how a ferrous piece of steel is magnetized: by aligning some/most/all of the molecules (atoms) that make up the metal so they are all 'aligned', or spinning the same direction. Think of this as instead of all the individual molecules just randomly spinning in different directions/rotations, they are all made to spin/rotate in exactly the same direction/rotation. They all align with each other, which aligns each of their individual magnetic fields, so their individual fields add together instead of cancelling each other out.

From this:


To this:


See how their magnetic fields are all aligned with each other^...

Why is this important to understand? Because the magnetic field that radiates out from a conductor, as a result of current flowing through a conductor, is (1) of the (3) things needed to have induction: the magnetic field.

The inherent nature of this magnetic field is such that it constantly increases & decreases from zero to maximum with the changing frequency of the circuit. For us here in America (fuck yeah), This frequency, abbv as HZ and measured in hertz (hurts), is 60 cycles per second. That means that the current flow starts at zero_then increases to maximum positive alternation (current flowing one direction)_decreases back to zero_then increases to maximum negative alternation (current flowing the opposite direction)_decreases back to zero again. This continuous cycle of increasing> decreasing> increasing> decreasing> etc...creates an ever expanding / collapsing magnetic field that not only gets bigger/smaller as the current flow increases/decreases, but also changes polarity (rotational direction that it spins/radiates around the conductor) as the cycle passes the zero line and changes from positive to negative alternation.

That constant increase/ decrease of the magnetic field is one of those (3) things needed for induction: relative motion. When another conductor is brought close enough to this expanding/collapsing magnetic field, the flux lines from this field "cut" into this adjacent conductor and induce a voltage into it. If this conductor is connected in a circuit then a current will flow in it.

There are a few main parts of an AC 3-phase motor:
-frame
-stator (stationary coils wound within the frame)
-shaft
-rotor (permanently affixed to the shaft)
-bearings
-bell ends...

So when a voltage is applied to the stator windings, a subsequent current flows through them. This current creates a expanding/ collapsing magnetic field. This field then "cuts" the metal (cast aluminum) rotor which causes currents to flow within it. Now how does the rotor actually spin? Let's discuss Lenz's Law.

Lenz's Law states that an induced voltage (and subsequent current) is exactly 180 degrees opposite polarity from the applied voltage and current. This also means that each of their respective magnetic fields are of opposite polarities at any given time. This difference in polarities, along with the ever changing magnetic field (60 times per second, per the frequency) causes the magnetic field of the rotor to constantly be pushed and/or pulled by the constantly changing stator magnetic field.

Voila! Rotation is achieved via magnetic fields, which occurs due to current flowing, which occurs because a voltage was applied. Simple as pie!

*Note that the relationship between the (3) separate phases is such that, at any given time, any one phase is 120degrees out of phase (or different than) from the other (2) phases. What this means in that, looking at the sine waves of a 3-phase circuit or system, not only are the polarities (positive or negative alternation, which is the direction that the current is flowing) varying, but the amount of current that is flowing is different. This results in (3) separate magnetic fields radiating out from their respective coils, with different polarities & strengths, that are cutting the rotor. If you could look at a cross section of a 3-phase stator, you'd see these (3) magnetic fields appear to be rotating around in a circle around the stator. In reality they are each, individually simply expanding/contracting & changing polarity. This "rotating" magnetic field is what push/pulls that rotor as separate, opposite polarity (Lenz's Law) magnetic fields are created in it.

Rotational speed can be changed in a a few ways, as evidenced by this equation RPM=HZx120/# of poles . So:
-changing the frequency is generally not possible because it is fixed, per the standard that all power plants generate at. That said, it can be changed locally by using a VFD (variable frequency drive). Also called an ASD (adjustable speed drive) and maybe others. A VFD "basically" converts the applied AC to DC, smoothed it out, and then regulates the output via pulses of both positive and negative to simulate an AC sine wave. The height of the wave is the voltage, while the length of the wave is the frequency. A longer wave will not allow as many alternations to occur in a given second, which changes the applied frequency, which slows the rotation. Simply reduce HZ in the above equation and the RPM will get smaller.
-# of poles is the individual qty groups of coils that are wrapped in a stator (for any given phase). The less poles, the faster it'll spin. The more poles, the slower. The number of poles is fixed by the manufacturer and cannot be changed by you or I.
-the 120 in the equation is actually 2x60 but I don't remember what this is. It isn't a variable that we can alter either.

AC single-phase motors work just like 3-phase motors, with one general exception: They cannot start to spin (rotate) by themself. Single-phase is basically (2) conductors, each with an exact opposite polarity. When single-phase is applied, the polarity of stator and rotor fields is such that they simply oppose each other no matter where along the alternation the current is. They basically shake, or vibrate back & forth, without actually spinning. A phase shift is needed and is achieved in a few ways:
-split phase motor_the stator is would with multiple coils, of different gauge wire. These are called the start winding (smaller gauge) and run winding (larger gauge). The different gauges of wire offer varying resistance to current flow, which changes the field polarity enough to create separate, varying magnetic fields and polarities. These varying fields then allow the stator to start to spin. Once spinning fast enough, a centrifugal switch opens and removes the smaller stator winding from the circuit so that it doesn't stay energized and overheat/ burn up
-a capacitor-start motor utilizes a capacitor (commonly electrolytic type) wired into the start winding to create a phase shift between the start & run windings. It starts similarly to the split-phase motor and is also removed via a centrifugal switch.
-a capacitor start and run motor utilizes a capacitor as the cap-start motor does, but it doesn't remove the cap from the circuit. These use oil-filled capacitors.
-a shaded pole motor is that little, loud fan above you when you are sitting on the shitter. It has a shaded pole (big coil) wrapped around the core which creates enough phase shift to cause the rotor to spin

Each of the above has different characteristics such as torque. From most to least:
cap-start-and-run
cap start
split phase
shaded pole (virtually none)

There are other types of motors too.

Transformers are basically a motor without a rotating part. Instead of a solid rotor it has a separate coil of wire wrapped intimately to the first coil. The applied voltage (and subsequent current) causes a field to be created in this coil, which is called the primary coil(s). The second coil (called the secondary) is induced into by the primary mag field, which creates a voltage and causes a current to flow within it. To change the voltage, we 'simply' vary the ratio of coils ;number of wraps of wire) between the primary & secondary windings. Voila! Transforming one voltage to another.

Now, there are more aspects of this such as the relationship between applied current vs induced current, the configuration of the system (wye vs delta for a 3-phase system), and others. There is just to much to type and I gotta get to work.

Induction makes the world go 'round...

ETA: *Added some info above to describe/ explain how the (3) phases work to cause rotation...

In a DC ckt, electrons flow from an excess (negative) to a deficiency (positive).

In AC, there ain't no positive or negative or a single direction that current flows...

This lectricity stuff ain't that hard...