dmottaway
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| posted on 13/3/06 at 05:26 PM |
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speed control/governor
have an engine gathering dust in the corner. thought I might put it to use driving a generator, put am stumped as to how to devise a governor for
it.
any ideas, the locost-er, the better?
dave
Somewhere, in Texas, a village is missing its idiot.
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Jon Ison
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| posted on 13/3/06 at 05:41 PM |
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I would have thought summat too lock the throttle position you could set under load ?
Like a choke lever on the throttle cable maybe ?
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stevec
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| posted on 13/3/06 at 06:05 PM |
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What about something like this. 
http://www.railway-technical.com/governor.gif
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MikeRJ
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| posted on 13/3/06 at 08:19 PM |
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quote:
Originally posted by Jon Ison
I would have thought summat too lock the throttle position you could set under load ?
Like a choke lever on the throttle cable maybe ?
No good for a generator, any change in load would cause the speed to change.
You might try something like the old petrol lawnmowers used, basicly a spring loaded flap that gets pushed out by air from a fan. In the old Briggs
and Scrapiron, the fan was part of the flywheel/magneto, but any kind of engine driven fan could be used.
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Jon Ison
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| posted on 13/3/06 at 08:26 PM |
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depends on engine and generator output i guess.
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dmottaway
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| posted on 13/3/06 at 10:44 PM |
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thanx for the replies!
my first thought was the railway device from stevec, but couldn't figure how to drive or calibrate it, let alone make one.
I really like the wind driven flap idea - will ponder that one some more!
the notion of using a megasquirt also crossed my mind. surely it has some sort of out put that could be used to drive a stepper-motor to control the
throttle. then it becomes complicated, overkill and not really in the locost philosophy.
thanx for the help.
dave
Somewhere, in Texas, a village is missing its idiot.
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MikeRJ
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| posted on 14/3/06 at 11:19 PM |
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If you want to go technical then I had a plan to upgrade a cheapy generator that my cousin brought to me for repair...but couldn't be arsed in
the end.
I was thinking of using a servo motor (as used in radio controlled models) controlled from a PIC micro. The PIC would measure RPM from the generator
output and use a digital PID control loop. You could get a very stable 50Hz output with the benefit of much better transient response than mechanical
governors could ever provide.
You could build something simmilar purely in analog using a frequency to voltage converter (e.g. 555 time in monostable mode with low pass filiter, or
4046 Phase Locked Loop) with an analog PID control loop which could drive something like a solenoid actuator, as used in idle control valves etc.
[Edited on 14/3/06 by MikeRJ]
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