TCI Replacement 2020 It Works

Paul Sutton said:
I did a side experiment by holding at 1500 rpm (6000 pulses per minute) and varied the distance between the coil core and the magnet:

0.25 mm 5.9V 1.2mA
1.0 mm 4.7V 1mA
2.5 mm 2.9V 0.5mA
Click to expand...

Awesome experiment there. The info on spacing is something I was going to to work on tonight to try and compensate for the stronger replacement magnets.
Your relay coil is pretty close in characteristics to the pickup coil. The TCI pickup is 720 olms but the principal is the same.

The ma currents involved are not going to generate a lot of heat vs the Amps that a charging coil would make.


So like I said back when first discussing what to do with the unterminated coil shorting it probably wouldn't hurt it to short the coil, I'm approaching the whole Gonzo thing with an abundance of caution. I don't want to break anything.

Getting the info on pickup spacing is very helpful to the project. Several people have asked about the spacing and I had hesitated about answering without empirical data at hand. Now we have it.
 
"I did a side experiment by holding at 1500 rpm (6000 pulses per minute) and varied the distance between the coil core and the magnet:

0.25 mm 5.9V 1.2mA
1.0 mm 4.7V 1mA
2.5 mm 2.9V 0.5mA"

I was waiting for someone to pickup on this spacing experiment. The signal voltage looks to be good, but this data is essentially that for an XS at 6000 rpm i.e. 1500 rpm x 4 magnets. I gave another value for 330 rpm and a 1 mm spacing which is essentially an XS at 1320 rpm just above idle. With a 1mm spacing the signal is a very poor 0.95V. I assume the XS pickup will give a higher voltage but we start to see how spacing is critical for signal quality at low rpm.
 
This can probably be worked out by trial and error. Unless there is a way to setup the 2M butchered Gonzo with Oscilloscope tabs added to monitor the pickup signal before and after the circuitry has done its pre-conditioning??

Have fun.
 
Nice lil' experiment, Paul.

A shorted trigger coil will produce only a few milli-watts. Insignificant compared to the engine heat in that area.

Measuring narrow width pulses with a voltmeter can be misleading, since the meter is usually reporting averaged RMS, not the voltage spikes. Yes, a good place for hanging a scope. A circuit that triggers on the rise, or slope of a pulse is tricky, since the position of that slope changes with wave width, shape, and magnitude.

Heating of PMA coils, anybody remember this thread?

http://www.xs650.com/threads/stator...wires-at-the-phase-connections-melting.30742/
 
TwoManyXS1Bs said:
A circuit that triggers on the rise, or slope of a pulse is tricky, since the position of that slope changes with wave width, shape, and magnitude.
Click to expand...

I have read in several places that these boxes trigger on the transition of the pulse from positive to negative which in theory should occur in the middle of the magnet.
 
2M, it may be that the low voltage observed at 1320 pulses per minute is due to the meter's limitations with AC as you mention above. It would be worth using an Oscilloscope to get true voltage reading, but I do not have one - damn. Would a diode and electrolytic capacitor get me closer to the truth?

Thanks.
 
As mentioned above by Team Junk in Entry 544 we do not want the input signal to swamp the Gonzo conditioning circuitry. To illustrate this point I collected some extra data from my latherometer. I used a silicon diode and 1nF ceramic capacitor in series as the load to improve my voltage readings using DC mode and the probes across the capacitor:

RPM (Voltage)
800 (0.9V)
1320 (1.6V)
2200 (2.8V)
6000 (9.5V)
As expected the signal from a magnetic pickup increases significantly with rpm, a principal exploited in many speed measuring devices. The Gonzo has conditioning circuitry to deal with this, but being designed for a reluctor will it cope? Practical hands on road test experience to date indicates it will.

Swamping of the conditioning electronics is more likely to show up at high rpm under load rather than on the stand in the garage. We could get very technical with the Gonzo but nothing is more simple than just fitting a unit and then going for a ride and feeling and listening to how the XS engine runs under different conditions - This of course is the spirit of this thread. So no more of this electronics crap from me!

Note: As a side to all this, those who want to design their own ignition system could utilise this voltage versus rpm effect to set the timing advance using an AD converter and microprocessor.
 
What got me started on the pickup voltages was a post on this thread that I can't find now by someone who replaced the stock rotor magnet and now his stock TCI box is not happy. I now suspect his magnet is reversed.
The gonzo seems happy with the stock pickup and magnet. We will have to wait and see how things go with the conversion of the pre tci rotors. On the test stand, a neo magnet with the chinese pickup works fine.
 
What are you thinking of gggGary, expand a little? To me a steel slug would be kind of like a reluctor setup if the coil has a magnet set behind it?
 
gggGary said:
Would a steel slug in place of the magnet work?
Click to expand...
One thing I'm gonna try is replacing 3 outer screws on the rotor with brass and leave the plain steel one right next to where the magnet would go. If that works, it would have the added advantage of putting the trigger closer to the center of the stator cutout because the screw is about 20° advanced of where the magnet would go. Would make modding the rotor much easier.
 
I wander but I just attached the turn signal bulb to the orange TCI output wire other side to +12 got some interesting displays as i cranked the motor, pretty good output test but needs some more play.
 
Found it.
MacMcMacmac said:
I may be imagining things, but I swear I am getting a lot more kickbacks at startup with the neo magnet even with the stock system.
Click to expand...

MacMcMacmac
2 things.One is the possibility is the wrong face of the magnet is facing out. If so you will have to swap the idle and advanced pickup leads.

The other is what we have discussing here lately about to much voltage from the pickup. If that is the case then a resistor in series with the centertap lead (the black and white wire). Let us know.
 
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