More Power!

[Pastor Gordon]

I was wondering how I might get a bit more power coming from my little "skate wheel" machine...

At the moment, I have 4 transistors working... each one of them have a 100 Ohm 1/2 watt resistor on them, and I have a 100 ohm resistor inline with my 1k potentiometer(wire wound, NOT linear)...

Would I get more power out of the machine if I used a smaller resistor on my transistors? or possibly using a smaller resistor inline with the pot? Or would I just blow the transistors if I did that?

Your thoughts anyone????

[Aaron Murakami]

When it speeds up, how many gears does it shift until it gets to top speed?

[Pastor Gordon]

When it speeds up, how many gears does it shift until it gets to top speed?

uhm... what??? lol It speeds up and slows down according to where I set the potentiometer... but "gears"???

[John_Koorn]

Hi Pastor,

As the SG comes up to speed it reaches points where the number of spikes per magnet pass decreases. This is what some people refer to as "shifting gears".

It's reasonably easy to see this with larger rotored SG energizers, but harder with smaller "skate wheel" SG energizers.

Can you post a scope shot of your energizer at full speed. From there we can tell if you have tuned to its optimum.

John K.

[Pastor Gordon]

Hi Pastor,

As the SG comes up to speed it reaches points where the number of spikes per magnet pass decreases. This is what some people refer to as "shifting gears".

It's reasonably easy to see this with larger rotored SG energizers, but harder with smaller "skate wheel" SG energizers.

Can you post a scope shot of your energizer at full speed. From there we can tell if you have tuned to its optimum.

John K.

Unfortunately, I don't have an oscilloscope... All I got is my multimeter, and my ear. It does have 2 noticeable "spots" where it slows down or speeds up... I've been judging my output with my meter. I hook it inline dialed into the "amps" setting between the positive output of the machine and the positive lead on the battery. Ill tune it until I get the highest output of mAh flowing through the meter... I know it's not the best way, but it's the only real way I have at the moment.

[Aaron Murakami]

Unfortunately, I don't have an oscilloscope... All I got is my multimeter, and my ear. It does have 2 noticeable "spots" where it slows down or speeds up... I've been judging my output with my meter. I hook it inline dialed into the "amps" setting between the positive output of the machine and the positive lead on the battery. Ill tune it until I get the highest output of mAh flowing through the meter... I know it's not the best way, but it's the only real way I have at the moment.

Ok - yes on what John K is saying about shifting gears.

Let's just say you set it midrange on the pot and let it get to the highest gear...

Take an alligator clip and put both leads on both sides of the fixed resistor to bypass it. Do it just for a few seconds and see if it starts to significantly speed up. If it does, then let it rip. When it gets to a new top speed, remove the alligator clips and you can actually achieve higher speeds with the same resistors. It just won't get up to those speeds by itself and requires that little trick.

You should be able to see significantly higher speeds with significantly less draw.

[wrtner]

Unfortunately, I don't have an oscilloscope... .

Put winscope into Google. It is a free download.

It has a low freq response but for SG work, it should be helpful if not ideal.

You will need a cable from your soundcard inputs and some fat variable resistors which should stop you blowing it. (Severe warnings come with the documentation).

If and when this solution runs out of road, Ebay should get you a cheapish scope.

[BobZilla]

Pastor,
Have look at this old video I shot to demonstrate multiple firings per pass. This is the "gears"...

Link:
http://1drv.ms/1R5RnN2

[Pastor Gordon]

Ok - yes on what John K is saying about shifting gears.

Let's just say you set it midrange on the pot and let it get to the highest gear...

Take an alligator clip and put both leads on both sides of the fixed resistor to bypass it. Do it just for a few seconds and see if it starts to significantly speed up. If it does, then let it rip. When it gets to a new top speed, remove the alligator clips and you can actually achieve higher speeds with the same resistors. It just won't get up to those speeds by itself and requires that little trick.

You should be able to see significantly higher speeds with significantly less draw.

Ok, I get the "gears" thing... however, you say the "fixed" resistor??? I have 4 of them (4 transistors) So should I be bypassing all 4 resistors to do this? or should I get rid of all the resistors except the one going to the pot, and then bypass it?

Another thing I have noticed... when I get the best mAh output, none of the neons glow at all (when there's no battery hooked up). I've seen people tune so that they get it to right where the neons start to glow, then back off just a little and they say that is there "sweet" spot. But I get a higher mAh output quite away from that spot... The neons will glow if I turn up the juice from the pot, but the mAh output goes down. I don't do this often btw, for fear of frying yet another transistor...

Pastor,
Have look at this old video I shot to demonstrate multiple firings per pass. This is the "gears"...

Link:
http://1drv.ms/1R5RnN2

Gotcha... I get something similar on my little wheel... it is a bit harder to tell with the smaller setup, but It is noticeable. I appreciate the video, I really like your setup with the solid shaft and fixed bearings. I tried to make something similar, but never could get it quite right... I'm still working on my big wheel though.

[RS_]

be very careful with using your sound card with a pc software O-scope on a SG or SSG, with the leads hooked to the C -E on a transistor will kill your sound card....
you need a opto isolated input to your sound card... look for circuits on line for this.....
or buy a cheap version of a PicoScope
https://www.picotech.com/products/os...pe?source=MadC

[Pastor Gordon]

Would something like THIS give me the readings I need??? If I purchase something, I want to use it for this small machine, as well as a larger one when I finish my build.

[RS_]

yes... that will work

[Pastor Gordon]

yes...

But i do suggest that you get a 2 channel model, more things you can do with them.....

this one says that it has 2 channels...

Specification
Interface: USB2.0
Number of channels: 2
Input: 1K Hz, 3.25V level standard reference square wave output
Bandwidth: 20MHz
Maximum sampling rate：25M sps (single), 50M sps (dual channel)
Vertical resolution: 8 Bit
Voltage range: ±5v, can be extended to ± 50v through X10 table pen
Noise size: ± 25mv (500mv/div stalls)
± 10mv (200mv/div stalls)
± 8mv (100mv/div stalls)
± 4mv (50mv/div stalls)
Coupling ways: DC coupling, AC coupling
Triggering conditions: Trigger level + rising / falling-edge trigger
Trigger: Auto, Normal and Single Trigger
Input impedance: 1M/25pf
Storage Depth: 4K bit
Power: < 2 W
Automatic measurement: Maximum, minimum, peak to peak, frequency, average,
RMS, rise time, Positive Width, Negative Width, Duty Cycle
Dimension: 12 x 7.5 x 2.5cm