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  #21  
Old 26-12-17, 21:51
learnerdrive learnerdrive is offline
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Quote:
Originally Posted by T13EES View Post
Quote from a USA bikey just for your information :-

" The nature of charging systems generally offers two paths.
One creates constant voltage, and varying current.
The other works inversely to that, being constant current, varying voltage.
The 1st one has more drag but works better at low RPM.
THe last one is what we all have, a constant current system, and works
better at higher RPM and offers less electro-mechanical drag.
The trade off is the difficulty of regulating those voltage swings.
Dropping voltage makes heat. Dealing with tons of it creates engineering challenges.Heat degrades things.( think Turkey in the oven) makes them softer and more crunchy at the same time.
For electronics this makes things fail obviously.

In our three phase AC generating apparatus, theres really only 3 parts.
The Stator with its magnet rotor, and two electronic items, the rectifier and the regulator. In most all cases except one These two items are married together within centimeters of each other, and one bakes itself and the other, also .... mercilessly.
The regulators sole ( or 'soul' after it dies ) purpose in life is to keep the rectifier from sending anything over 16 volts to the battery.
It simply sleeps until the threshold is reached and clicks on.
Advanced ones have a taper as they activate. (shhh)
The rectifier is really only 6 diodes in basic form. 2 diodes per phase, creates a nice DC pulse to the battery, via the regulator. They are kind of dumb, doing a boring job of getting real hot while just slicing up sine waves into 3rds. They are intuitive as a peice of rock salt.
The regulator watches the voltage in the system,allowing anything under a maximum setting to pass straight to the battery from the rectifier.
The regulator is where theres any intelligence, or could be.
when voltage exceeeds the limit set by the regulator something interesting happens where you can also see the difference in traditional regulator rectifiers and the newer comming generation.
When the regulator senses the peak has been exceeded, it fires the gate on an SCR that simply ggrounds out one of the 3 phases comming from the stator. Brutally simple, this direct short to ground creates massive heat in the SCR. when the SCR fails, you have runaway voltage.
The SCR ( sillicon controlled rectifier ) is like a simple 3 pole relay with no moving parts. In our circuits they are gateways straight to hell... literally.
Its a path to ground and heat is the product. On cheap R/R models that only ground one set of windings of the stator, the stator gets damaged much sooner. Advanced models of R/R have an SCR on each stator winding to evenly ground out the stator, creating an even heat distribution pattern in the windings themselves. This makes a longer lasting stator.
None of this matters at all of course if you ride slow like a granny.

Regulator circuits fail too, getting a career baking (BBQ) by riding piggyback on hot rectifiers. when they fail it can go two ways.
Remember the regulator is the brains of the system.
Mode A is where the regulator fails to fire the SCR, closing the circuit.
Mode B is where the regulator holds the gate open, and fries stuff by overcharging.
I prefer mode A.

Your frame is a massive capacitor (electrolytic at that).
Connect your negative 1st, and dont spark your positive cable ot the resulting spike in voltage will pop any cheap or stock R/R.
And if it dont kill it good the 1st time, you can rest assured its been damaged.

About heat distribution.
THe rectifier diodes (6) make most of the heat, 70% at least.
But those SCRS when you are spinning the motor fast are giving quite a bit. One of my discoveries, by chance was how only 3 of the 6 diodes make any heat in certain arrangements. I wont spam or give away hard earned secrets, but there is a design coming that creates half the heat at full power load based on this data."
Now that is informative and written in the sort of language I can understand (mostly!). Thanks.
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  #22  
Old 27-12-17, 07:50
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Adam Adam is offline
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Mofset type regulators have a lower resistance and therefore generate less heat and last longer.
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