Welcome to Electrickery...a beginners guide


( Yes I know, 'Catweasel' used to say it...Why don't YOU make something up for a change!)

Electricity is what we call it, when a great number of very annoyed, but invisible, Gremlins, gallop around your wiring, lighting your lights and spinning your starter motors.
These fellows are so tiny that, even if we could see them, we could not count them. Apparently you can have six million, million, million Gremlins galloping through your bit of wire in a second.
Luckily some earlier mortals developed meters that can measure this great dollop of Gremlins as they hurtle by. This dollop is called an Amp, hence the Ammeter (or Amp-meter).
Thank goodness for that! It makes electrical sums a bit easier, especially, if like me, you struggle with just one or two noughts on the end of a number.

Before we continue with this technical description we need to understand Wiring and Switches. Wiring, ignore the copper bit and look at it as a hollow plastic tube down which the Gremlins flow, the bigger the hole in the tube the more Gremlins you can get down it in a given time. Switches are like valves or taps in your house plumbing. When a switch is on, it’s like opening your tap and the Gremlins rush through, when a switch is off it’s like closing your tap and the Gremlins stop flowing. Right then, where do these Gremlins live when they are not hurtling along your wires? The answer is two places, The Alternator and the Battery.

The Alternator is where they go for a snooze when the engine is not running. They are no good to us asleep, we need them moving, so we wake the little buggers up by spinning the alternator. This really pisses them off big way (it would me, if someone spun my bed around at a few thousand revs), so they all rush at once to try and squeeze out of the only exit, which we call the Positive Terminal*. This squeezing creates a pressure, which we call Volts, and we can measure it with a Voltmeter.

The Battery is a sort of prison where we trap some of the pressurised little buggers from the Alternator (or a Battery Charger). We need to keep them jammed in there and hopping mad so that they will rush out of the Positive Terminal* when required, giving us electricity even when the engine is not running. To do this we keep them in Sulphuric Acid, believe me they rush out of that positive terminal right smartish when we operate the relevant switches.
[*Actually they leave by the Negative terminal, but ignore this or we will all get totally confused.('Yes and I know how they decided this....Chris)...]

So we've access to two sources of aggravated gremlins bursting to rush down our wires to do electrical work for us as soon as we switch them to lights, motors and ignition transformers.
Lights. Picture a stream of Gremlins spewing out of one of the Positive Terminals, and rushing down your lighting circuit until they come to a tight restriction, the lamp/bulb filament. This tight restriction is too small for the leading Gremlin to get through, BUT with a multitude of its mates shoving from behind it gets forced through, as does each following Gremlin. The resulting friction heats up the filament until it glows white-hot
The number of Gremlins (amps or fractions of an amp) that pass through the filament is directly proportional to the restriction. We call this restriction a Resistance and we measure it in Ohms, using an Ohmmeter. The Power of the light created is measured in Watts.

Bike Electrics, a Technical Description


Starter Motor.
Because it’s a bit greedy for Gremlins, you get a great horde of the buggers hurtling down that large bit of wire into your starter (lots and lots of amps). When inside, some go to the ‘coils wrapped round metal thingies’ in the fixed part of the motor. And some go to the spinning round shaft bit.
The ones that end up in the fixed part (Field coil) whiz round and round the laminated metal creating a magnetic force between its pairs of poles. This invisible magnetic force behaves like lots of thin, but very strong pingy elastic bands. If you deflect them, they want to ping back rapidly to their original position.
Those that go into the spinning round shaft bit (armature), pass through the brushes and opposing segments of the Commutator. The commutator segments are connected (if the solder holds) to the ends of a number of thick loops of wire. In these, the Gremlins set up a magnetic field that radiates out from the loops cross section, like the concentric circles that radiate out from a stone chucked in a pond.
Now, when one of the armature’s loops gets between the poles of the field coil, the concentric circles deflect the pingy elastic until the pinginess is so great that it shoves back against the concentric circles, and therefore the loop, this spins the shaft round on its bearings.
Ignition Transformer or Coil Inside we have the now familiar laminated lump of metal but this time it has two windings or coils wrapped round it.
The first one (The Primary Coil) is connected to the battery (or alternator once the engine is running) via the ignition switch/s and the points. The second one (Secondary or High Tension Coil) forms a circuit through one plug, across its gap to the engine mass and back across the other plug gap, and through the other HT lead back to the HT coil.
With all switches and the points closed, amps whiz round the Primary coil stuffing magnetism into the laminated core, until the points open. At this point the magnetism wants out, the only place it can go is the HT winding where it converts into a small number of Gremlins that are very, very highly aggravated (thousands of volts). Now these high voltage amps will easily jump across the gaps in your spark plugs, igniting your petrol/air mixture (one cylinder only firing, the other spark is ‘wasted’).
By A.Gremlin-Trainer, Bs Hons'
( And don't Email me asking who 'Catweasel' is.....or what a Bishons is -either)