Acts/ Dictates/ Mandates/ Mantle - Amy's Thread (Page 19 of 77)

Published and out there. Also entered in the contest and resubmitted so that people will see it and get points if they want. 99% of all comments were integrated.

Ouch!  I see you used  the adjective for Coral's soreness.

Okay, for those of us who can't remember eletricity 101, how does grounding work and why is it needed?

And how/why does grounding work in your story?

Thanks
Dirk

Amy ... I have a few more things to mention on Honor.  I'll do it as soon as I'm finished here.

Norm D ... Grounding and electricity:

There's a whole layer cake of theory on grounding, and I don't have the expertise to go many layers up.  But then, you'd have a hard time following.

So ... some basics about electricity.

The basic unit of electricity is the electric charge.  Negative charge is carried by electrons, which move easily through conductors.  Positive charge is in the nuclei of the atoms, which are fixed in place in solid conductors.  In liquids, they are still hard to move because they are millions of times heavier than electrons.

Charge is measured in Coulombs, each Coulumb being about 6.24x10^18 electron charges.
Electric current is charge in motion: an Ampere is the movement of one Coulomb per second though a notional surface.  (An electric current creates a magnetic field around it.)

Electric fields (electric potential) extend from positive to negative charges; positive and negative charges attract each other, and if allowed, current will flow 'from positive to negative', which means electrons move toward the positive charge.

Now ... how much voltage (potential) does it take to propel that current from one point to another?  In the simplest case, current flows in proportion to voltage, and that proportion is called conductance.  We usually talk of conductance by its numerical inverse, resistance (ratio of voltage to current).  The amount of resistance follows from the bulk properties of the materials involved (silver has a very low bulk resistance or resistivity; fused quartz has a resistivity 10^17th higher) and from the geometry (multiply by length, divide by cross-section area).

What this means is that even a poor conductor like the earth beneath us can act as a good conductor if we get a good cross-section--and there's a lot of earth to get that cross-section.

And  ... how much charge do you need to pile up to create a potential of one volt?  That depends on two things: the geometry of where you're piling up the charge, and the bulk properties of the materials that the electric fields penetrate.  (The bulk property is called permittance, and the proportion of charge to voltage is called capacitance.)

The earth is a big object, and you can pile up a lot of charge in it without much changing its electrical potential relative to anything.   (Electrical potentials are always relative to each other or to something.)

So in concept, electrical earth (or 'ground' as we Yanks say) is a reference point that can absorb or provide infinite current with no change in voltage.

Of course, nothing's perfect.  Still, if you get an accidental connection to a 120 or 240 volt power line, a good connection to ground can divert enough current to pop a circuit breaker.  (And Ground Fault Interruptors detect ANY leakage to ground, by looking for a difference between the incoming and outgoing currents.)

The 'ground' potential from one part of a building can differ from another by several volts, for a variety of reasons.  This can cause havoc with the old coaxial-cable ethernets, which is why the more recently designed twisted-pair networks are transformer-coupled at both ends.

Within an electronic circuit, 'ground' is a place in the circuit network that serves as a reference point for (almost) every voltage and a current sink for nearly every power supply element.   There are different symbols for circuit ground and 'chassis' ground, though they may in fact be the same.

Resistivity is a bulk property of a material and is unaffected by any but the highest frequencies.  Capacitance is more interesting.  Every bit of geometry in the layout of a circuit introduces capacitance.  At frequencies below ten megaHertz or so, only the devices built as capacitors have gross effects; the effects of stray capacitance are generally small.  (But not always; the product of capacitance and resistance determines the frequency at which effects begin.)

Analagous to and inverse to capacitance is the property called inductance.  It follows from energy stored in the magnetic field induced by a current and acts like inertia on the flowing current.  (The stored energy depends on the amount of current, the geometry, and the properties of the materials which the magnetic fields penetrate.)  Where capitance means that voltage grows over time with current, inductance means that current grows over time with voltage.  (Resistance divided by inductance tells you the frequency at which inductive effects become significant; in both cases the 'time constant' is one over the angular frequency, and the angular frequency is two-pi times the cyclic frequency.)

Which is more than you ever want to know, but it gives another important use for grounded conductors in circuits.  A 'ground plane' can keep the elecric and magnetic fields generated in one part of a circuit from influencing those in another.  And, in a behavior called 'a transmission line', it can help a high-frequency signal move through an adjacent conductor in an orderly way.  (Transmission lines lie between the behavior of ordinary circuits and the behavior of radio waves.)

Now that's =way= too much information!

Thanks, NJC. I appreciate the time you took for this.

I couldn't follow all of it, so let me try with a simple example. A good old-fashioned Shoddy-brand hand mixer plugged into an old-fashioned NON-grounded outlet. Those were fun! Based on what I remember, the mixer is tapping into the electrical circuit that flows through the house, fed from the utility lines outside. If a part of the insulated wiring inside the mixer becomes exposed/worn, the current can flow/leak out from the wiring into other parts of the mixer (e.g.,  the spinning metal egg beaters or the on/off switch), leading to a potentially painful zap, if touched. Good so far?

When it zaps me, does that have anything to do with me standing on the Earth, or would it jolt me even if I were floating with some of Amy's magic?

Now, let's extend that to grounded outlets. Once again, the wiring inside the mixer is worn. I assume some or all of the leaking current flows through the ground wire into the outlet and down to the Earth. Yes? Is it just some of the leaking current that's diverted? So I can still get zapped, just less so?

If my basic assumptions here are wrong, then I'm a hopeless case.

Thanks.
Dirk

P.S. Amy, don't go far. When/if I understand this, you're next.

If the wires are degraded in your old mixer, and the positive wire touches the case, then the electricity will look for a path.(imagine a dam) The water will be contained until it finds a way out of the dam or a sluice opens. If you are wearing rubber shoes or rubber gloves, then the power has no path. It won't shock you because it can't cross the barrier of shoes/gloves. If you have bare feet, the sluice is open, electricity flows across your body and down your closest leg. You feel a shock.

Let's say you are holding the mixer and your elbow is touching the wet counter. The power crosses your hand and goes out your elbow. You feel a shock.

Does this answer your question?

When a Mage grounds, they connect to the earth and a well of potential power. Each Mage has a reserve carried within them. Once they ground, they can cast spells and replenish their reserve each time. The problem is that the reserve can only handle a certain charge without residual heat and tissue damage.

For example, the motor of your mixer wouldn't power an air conditioner. This doesn't mean the mixer couldn't try. Each Mage can perform a Hail Mary and burn down the house. This could leave them disabled or dead. Or fizzle and do nothing.  This is why new mages explode if they don't learn to ground or accidentally over-reach with a powerful spell.

What Kha did with his thesis was discover that he could rank a mage's ability by watching for changes in the growing mage's reserve. Then he ranked the power of each spell so the new Mage would know what class of spells were safe to learn. Everybody scoffed until his students advanced quicker and (more importantly) didn't blow up. He also gave count limits so that each Mage knew how many spells were safe to cast in a row without taking overload damage.

Anver is second generation. He was raised within Kha's school. He has never overloaded or damaged his matrix. That's one thing that makes him so powerful.

Katerin was made into a Mage. She was forced into a mold of Alina's matrix and survived the experience. She never had a matrix. Instead, all her magic was carried within her wand like a battery. Once gone, the wand has to be recharged by proximity to Alina. Alina used the heartwood of her staff for her personal use. Everybody else has sapwood for their wands. In my story when Alina dies, katerin takes her mistress' wand and then manifests. The stress of being near the duel makes Katerin's matrix evolve into true Mage status.

Essentially, I used electricity as a template. But magic has slightly different rules because...well, because it is magic.

The motor of your mixer is probably a universal motor, which uses 'brushes', blocks of graphite which carry current into a surface sliding beneath them.  In the case of the universal motor, the sliding contacts are a split ring, creating a commutator, which connects the windings differently according to how the rotor is turned.

The motor of the air conditioner is almost certainly a brushless induction motor which requires AC.  The motor is completely immersed in the air conditioner's heat-transfer 'coolant', which cools the motor and, via a little oil mixed into the fluid, also lubricates the motor.

I beg to differ, njc. I don't think the Filbert Flange will mesh with the Grapple Grommet.
https://www.youtube.com/watch?v=FJ6jCM3UeZo

The older telephone central offices have basements filled with huge tanks of sulfuric acid, with giant plates of lead and lead suplhate hanging in them.  They're the backup batteries, and as it typical of lead-acid batteries, they can dump a lot of current.

Telephone central offices used to, and to a degree still do, run on -48 volts DC, which is the basic POTS voltage.  ('POTS' = 'Plain Old Telephone Service', and yes, it's an industry acronymn.)  This is carried by big copper busbars running overhead in the switch rooms.  Everything the maintenance and repair staff used ran on -48: the trouble lights, the soldering irons, all of it.  You clipped one side to an equipment frame and the other to the copper bar overhead, and you went to work.

One day someone was working overhead on something that required a wrench.  He dropped it and it made contact with the copper busbar and the steel rod that supported the busbar, both at once.  The busbar is insulated from its support, but neither was insulated from the wrench.  Thousands, or maybe tens of thousands, of amps flowed.  There was a blinding flash and a louder bang.  The wrench was gone--vaporized!

Now I catch up on promised photos.

Did I answer that sufficiently?

Thanks, Amy. I have a better understanding, but far from perfect. I find it very complex, even without the concept of the matrix. Why did you go with something so hard to understand? For example, mages draw power from the ground with their staffs into their reserve in order to cast spells. Yet, new mages have to ground in order to keep their overloaded reserve from blowing them up. These seem contradictory to me. The first case draws power, while the other sends it back, both by grounding.

I doubt you can simplify it at this point without a major rewrite of the books, but I look forward to reading the first book, which I accidentally skipped, to see how much I understand your explanation there.

Thanks.
Dirk