Re: Electrical Insanity with '87 CBR600

Rob Kleinschmidt wrote:

On Sep 16, 11:45 am, Rick Cortese <ricor...@xxxxxxxxxxxxx> wrote:


If I have it correctly, even the Hall effect sensors you<?> mentioned
are now considered "old tech." Not that they didn't work, just that a
lot of new designs are transconductance amplifier. If I have it
correctly, typically they will just have a coil around a magnet mounted
stationary with a steel/iron rotating part. That way you don't need 8
magnets or to spin the magnet(s) at 10,000 RPMs.


Actually, the Hall sender that I've looked at is an integrated
magnet and chip with a slot between them. What spins is
a slotted aluminum cup. The slotted sides of the cup pass
between the magnet and sender, intermittently blocking
the magnetic field.

If you can, test the rotating part with a magnet. I saw where rotating Aluminum plates were used as brakes in that LSR F104 jet with wheels and I will take your word for it if you don't have the time or ignition to test.

But it is hard to say just exactly what and how the ignition is implemented just based on physical layout. I mean it could even be a IR emitter/detector pair that does the switching. Could even be a Hall effect IC powering a transconductance amplifier.

Point I am trying to make is: Designs directly driving a SCR or transistor with current from a battery or magneto are kind of being relegated to lawn mowers and weed whackers. The amount of current output was proportional to engine speed. They needed to operate from near zero to 10,000 RPM which meant the output was sufficient at low RPMs and probably 20x what you needed at high RPMs. Feed 20x the current into a gate/base and you are looking for trouble. Much better to have a design where except for gate delays due to capacitance, there is a q.s. voltage rather then current is what matters. This could be as simple as a CMOS gate or amplifier replacing other amplifier schemes.

There are other ways of doing it. For example current limiting is available in several ICs I can think of off the top of my head and they would provide the same protection from high currents. Thing is I know of no designs that use them at the momment.

Rick
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