Cheap "Frequency meter" inspired moment!

[dubbleUJay]

I was inspired to this idea by a post from Chris over here:
http://www.microcogen.info/index.php?topic=392.msg2795;topicseen#new
He mentioned using a old record player, listening to the sound, to set the speed of a generator.

Now please bare in mind that I haven't tried this yet as I don't have any time at this stage, but if someone doesn't try it, I will probably in the distant future! ;-)

Remember those record players with the light shining inside a small window to set the speed accurately from "stripes"

By using a program called "Encoder Design" written by Scott Boskovich from "The Boeing Company", its very easy to print a encoder onto paper and stick it to one's crankshaft. (You just have to do the maths)
http://www.societyofrobots.com/downloads/Encoder_Design12.exe

AVG9 passed it on my PC, but always scan downloaded programs!!

Attached is a quick print I did with 50 decoder lines just to show what its capable of.
I haven't done the maths for the program to print stripes for 50Hz/60Hz or more correctly, for 650, 850 or whatever rpm the engines run at, but if one shines a incandescent lamp powered by the generator head onto it, wouldn't you be able to "see" if the speed is correct by looking when the stripes "stand still"?
One might have to use a light inside a short piece of pipe to direct it better, I don't know.

This might help the blokes without frequency meters

Wilhelm

I'm not sure if this can be done though, were are all the clever people?

[BruceM]

You'll need a strobe lamp, there isn't THAT much flicker on a Lister!

I see tachometers for $17 incl shipping at ebay.  Kit tachs for $5.  You can also use a model airplane tachometer set for 3 blades, then half the indicated rpm when pointing through the 6 flywheel spokes. 

[dubbleUJay]

Bruce, I might be mistaken, but I'm sure some times when I looked at my old "spoke" flywheel at night and the engine room was illuminated by mains power, I could "see" the spokes standing still at some "sweet-spot" rpm
By working out how many stripes one need for 650rpm and a flicker of 50hz to synchronize the seeing of the stripes, should that not work
I'm confusing myself now!

[dubbleUJay]

If 50-60hz is a bit fast, would a diode in series with the light for half-wave rectification not make it 25-30hz or what am I thinking

I've still got no idea if this might work

[Crumpite]

I was inspired to this idea by a post from Chris over here:
http://www.microcogen.info/index.php?topic=392.msg2795;topicseen#new
He mentioned using a old record player, listening to the sound, to set the speed of a generator.

Now please bare in mind that I haven't tried this yet as I don't have any time at this stage, but if someone doesn't try it, I will probably in the distant future! ;-)

Remember those record players with the light shining inside a small window to set the speed accurately from "stripes"

By using a program called "Encoder Design" written by Scott Boskovich from "The Boeing Company", its very easy to print a encoder onto paper and stick it to one's crankshaft. (You just have to do the maths)
http://www.societyofrobots.com/downloads/Encoder_Design12.exe

AVG9 passed it on my PC, but always scan downloaded programs!!

Attached is a quick print I did with 50 decoder lines just to show what its capable of.
I haven't done the maths for the program to print stripes for 50Hz/60Hz or more correctly, for 650, 850 or whatever rpm the engines run at, but if one shines a incandescent lamp powered by the generator head onto it, wouldn't you be able to "see" if the speed is correct by looking when the stripes "stand still"?
One might have to use a light inside a short piece of pipe to direct it better, I don't know.

This might help the blokes without frequency meters

Wilhelm

I'm not sure if this can be done though, were are all the clever people?

Just a quick mention if you haven't thought of it - you need the lamp to run off of the mains for this to work.
If you use the generator it will always look like it's in sync since the RPM and frequency are always locked together.
You need the mains to act as a reference frequency.

Hope I'm not preaching to the converted..
Daryl

[Chris]

WOW look at what I started. I'm impressed. A word of caution when working around A/C powered equipment esp in a noisy work space. Do not have a floresent light as your primary light source. It can produce a strobe effect and your, say table saw might look like it is turned off. Blade not turning. Ouch.

Regards,

Chris

[dubbleUJay]

You need the mains to act as a reference frequency.
Daryl

Thanks Daryl, you are right, I didn't think of it that way and its so obvious!
As I was saying, its just a thought at this moment.

It would be great though if someone can works out the print for a 50 & 60hz at various speeds and have it here for download.Then anyone can take it, cut it out, attach it temporarily to one's crank and shine a light on it to get engine rpm right.
If it works BTW, I just cannot get around to it right now 

[BruceM]

My thought: there's too much rpm variation from power stroke for a visual strobe wheel to work well, even with a strobe light source.

Tachometers are so cheap, I just don't see the point of a DIY project on this one.  But then there are wooden gear clocks being made every day.