What's the best tuning method?

[william]

Trying to find the best tuning method for the ssg bike wheel setup.

I read from the files in part 2 of fine tuning the ssg circuit is to have the bulb light three times. One method is to go slow then speed up to three clicks on the pot or go fast then slow down to three flickers of the bulb.

And what is the best milliamperes draw that I should see, 120?

Thanks

William

[greghaa]

William

I am not sure what you are reading but what you wrote doesn't seem to be how I have been instructed to tune. I have read and been told to start with high resistance
and decrease gradually until I have the lowest ampere draw with the fastest wheel speed. But that doesn't mean just get the fastest wheel speed. It will take time
to really see how the wheel behaves after each adjustment. Take your time and pay attention to draw and RPM's. Hope this is helpful in some way...

[Howard Wetsman]

William,
If you have a scope, you'll see that at high resistance there is more than one spike per firing and as you lower resistance, at some point, you get one less spike. If you don't have a scope you'll be watching this on the ammeter. As you decrease resistance, current goes up until a certain point and then precipitously falls without any loss of speed of the wheel. These points are referred to as sweet spots and they represent the change from, let's say, 4 spike per firing to 3 spikes. It feels like you're changing gears. I have heard that things should be tuned to one spike, which would represent the lowest amp draw sweet spot. However others have said that they get better charging results with one sweet spot higher. Of course that could be just because they're drawing more amperage so I've always tried to tune to the lowest amperage sweets spot. I'm not sure what you mean about the light flickering, unless you're referring to John K's youtube video of his LED set up. Basically, if I remember correctly, he had it set up so that, without a scope, he could see how many spikes there were at each sweet spot.
I think the amps you draw will be dependent on your coil and your build so there's not a specific number anyone can give you unless you copied their build to the T.
All the best
h

[william]

Thanks I got it now but I still want to get a scope to to use your method

[Kasper Westeraa]

Dear Howard.

Do you tune to "the high end" amp draw of the sweet spot? - meaning the first stable point after the "dip" in draw?

Kasper

[Howard Wetsman]

Kasper,
On the one successful COP greater than one set of runs that i did using a single coil bike wheel I used the lowest amperage sweet spot and had only one triggered spike per magnet pass. Others may do it differently but my interest is in getting the charging done for the lowest current.
h

[Barrie Castle]

Guys,

You can do it with a meter & an rpm meter. The old forum test reports used this method almost exclusively. It takes much longer, but saves you rushing out to buy the latest 'scope. What you want is the fastest wheel speed for the lowest primary current draw. Multiply your rpm reading by the number of magnets on Your wheel & divide this by the current reading. Allow about 5 minutes settling time for each potentiometer setting. Then you can post what you get here & compare with everyone else on an even footing. Then, once you've calculated the final "magnets per minute per milliamp" values, it's easy to see which is the highest, so sub in fixed values until you duplicate this m/m/mA value.

All The Best.

[caldovicd]

can you clear a little bit this for me "so sub in fixed values until you duplicate this m/m/mA value.", I am afraid I didn't understood

thanks

[Barrie Castle]

Sorry... missed your post. "m/m/mA" is short for the aforementioned "magnets per minute per milliamp". "Sub in fixed values..." refers to fixed single resistor values corresponding to pot settings. There's an improvement to this method that I developed myself, which I'll detail for you now:

On both of my builds, I started off using some of the best 10-turn pots I could buy in an attempt to avoid some of the problems others have had with using regular pots. Sometimes they blow, often tuning is difficult, stability is a problem & then finding fixed value resistors to match the results at a certain point is time consuming. And of course, you can't leave the pot in-circuit for the COP runs.

An easy solution to all of this is to use a custom-built Decade Resistance Box. I bought a set of "0-9" thumbwheel switches for about $13 each plus tax from SwitchesPlus in Melbourne. It's very quick & easy to solder in a set of 2W, tight tolerance (less than 0.1 ohm variation), surface mount resistors & wire it up very neatly & reliably. Then you can tune right down to one ohm resolution per step & leave it sit there when you're done. No need to power off, take measurements, etc, etc. Everything is already done for you, as the wheel is numbered & it's very compact. You can look up how to build your own decade resistance box online. Some mess about with rotary switches, but the wiring or schematic is still the same in principle. When I'm all set up for taking photos & uploading things online, I'll post what I've done & all my results, build method, parts suppliers with costs, so everyone is clear.