RPM regulation

[cato]

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by dacflyer:
CATO >> all the cruise kits have to have a speedometer input...<hr></blockquote><p>
Yeah, I figured that much. That's what we're suggesting you do with the magnets and hall effect sensors or the sprocket watching proximity sensors, make a fake speed signal to go into the speedometer input.

[dacflyer]

well all the ones i saw were needing the speedo cable input..via a cable,,,also the cruise control would have to be manually set each time..i want a set it and forget it deal...
knowhutimean......

[dacflyer]

Hmmmm , no one got any other bright ideas??
i still wait for the super brain to say something and AWWWWW me
i wait for the great guru to speak....

[toejam]

if you carefully examine a lawn-mower engines vane gogernor and apply the principals to your needs, a vane system may be the answer. Use a very light spring to hold the throttle open and position a plane surface on a pivoted arm that can intercept the air thrown from the cooling fan.By adjusting the size, spring tension and distance from the fan, you can get a decent speed regulation for the motor.You may have to baffle the air coming into the cooling system.

[desterline]

Is there a reason you don't want to go with existing comercial units?<p>Admiditly I haven't studied them much, but yours isn't the first generator in the world to need speed regulation - this problem has been solved by others in the past.<p>If it's just a cost issue, find one in a salvage yard.<p>-Denny

[dacflyer]

toejam >>> thas impossible to do with such a large engine,
no good....<p>
desterline >>> there is no commercial governors to buy...i been looking...also the reason i want to modify this engine is because the generator is fairly large but its belt driven....
and the engine i want to use is a 3 cyl. engine..
* sigh *

[desterline]

Dacflyer-
I find that difficult to beleive, considering all the generators, air compressors, and referigeration units powered by gas engines govenors must be available, if only as service parts.<p>However, if you want to build one yourself, I'd use a PIC.<p>With a pic you'd just measure the rpm, run a few calculations and output a pulse to the servo.<p>For the tacho, there's several places redily available to sense, engine coil pulses or the output of the generator would seem to be the easiest.<p>The PIC can redily control the servo, so the block diagram simplifies to :<p>1 sense
2 proccessor
3 servo<p>If you want a tach off the coil, the simplest implementation would be a resistor divider on the primary side, try 3.3k and 4.7, and feed it into the PIC. I'd probably add a zener to protect the PIC form the back EMF of the coil. <p>-Denny

[dacflyer]

desterline >>> its easy for everyone to say
"use a pic" but what bout the code??
i have no clue to these things...<p>if you say these governors are available then direct me to one somewhere....thanx..

[Will]

There are commercial units available - I've no idea how much they cost - They were reasonably priced when I used them in 1991/92 - I don't know what they would be now. They are manufactured by Barber Colman. They were comprehensive units i.e. they came equipped with PID features so that you could tune the control modes to your engine/application but they still needed the flywheel tooth sensor which I believe I mentioned earlier

[dacflyer]

ok, i looked at the site...but what would they call this...that i want...i looked..didn;t see nothing recognisable,,,,perhaps they call it something different???
thanx

[desterline]

Ahh, not familiar with PICs -that would be a difficulty. <p>How much electronics experiance do you have? And How much are you willing to spend?
How much interest do you have in doing other things with PICs?<p>My thinking here is that to get started with PICs you could spend anywher from $50 to $500 or more, depending on what other hardware you may or may not need. If your interested in electronics and have plans for the future, that's a trivial expense. If this is a one off and you'll never touch it again, that could be killer costs.<p>In the couple hundred dollar range I expect you could find someone to design / build it for you. That might be a better choice. <p>Where are you located, perhaps I could point you to someone local to help.<p>You might also try posting an offer to buy services on the piclist (www.piclist.com) over 2000 members world wide, many are profesionals in the field.<p>-Denny

[dacflyer]

Oh... a pic...you typed PID before... i have no use for pic's they too difficult for me and too expencive too... i keep searching to find what i want....someone here will have the answer solved soon,,,,just be patient

[Will]

dacflyer,
I tried to access Barber Colman - but only got a message saying they have been taken over by an Outfit named, I think, Smith's Aeronautic - I E mailed them and they acknowledged but thus far without any info - I will get back to you if they get back to me. I am absolutely certain that the units I mentioned to you are still manufactured and widely distributed but I also feel that they will be in the price range mentioned in the previous post i./e. a couple hundred bucks or so - Is that what you want or do you want to approach it on a hobby basis and try to design and build one ?

[dacflyer]

ok, wait to see what happens... hoping for something under 75.00 if possible...i keep searching elsewhere too...

[Bernius1]

Coleman makes towed poewr units, with less than 1% freq. & voltage drop under load. look for colemanMultiquip also makes 'em. MQ Power Tab But you can't get parts lists for their regulators. I tried Googly eyes to no immed. avail. I still say that a volt-drop sense on the output, fed thru a comparator (LM311 ?), triggering a 12V actuator on the throttle. An electric trunk latch opener, with a cable or chain, adjusted to a 'loaded' position. If you're crazy, (like me), you'd search for MSD ignition boxes with Rev limiter, & adjust to 1800 or 3600 rpm.
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