billj pump
Active Member
yourallabunchofgreatguys
Posts: 30
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Post by billj pump on Oct 3, 2006 0:48:49 GMT
i would like to experiment with a different size flywheel for maximum power output on my little steam engine as i want to drive a small dynamo unit, its bore is 3/4" x 1"stroke, it runs nice and sweet at around 1000 rpm(no load). by fitting a larger heavier flywheel will this increase the output torque? the flywheel that is fitted is 2"diam x 1" thick mild steel.
billj
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Post by ron on Oct 3, 2006 9:09:40 GMT
Bill
I wouldn't have though the weight of the flywheel [within reason] would have affected either the power output or the torque, just the acceleration and deceleration of the engine.
Ron
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jackrae
Elder Statesman
Posts: 1,335
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Post by jackrae on Oct 3, 2006 9:18:30 GMT
Output torque is determined by your piston dimensions, stroke and steam/air pressure.
Because the engine is effectively producing a sinusoidal torque capability to the output shaft a flywheel is used to "balance" out the peaks and troughs. The wheel simply provides an inertial mass which smooths out the power "pulses" and load transients by storing kinetic energy during the acceleration phase and releasing it during the decceleration phase.
Increasing its size above that required to provide reasonble inertial mass will result in sluggish speed response (perhaps no bad thing) but may result in loss of power due to increased friction because of bearing load.
Increasing the diameter of the of the flywheel will have a dramatic effect upon inertia since this increases at the 4th power of diameter, ie doubling the diameter gives 16 times the inertial effect. So a large thin flywheel can give the same effect as a small thick one but with much much less weight.
One advantage of the flywheel is that it will reduce vibration (providing the wheel itself is balanced).
If the dynamo you intend to drive is one of the old wheel hub style and it is directly coupled to the engine you may well find that it is enough of a flywheel in itself to obviate the need for one on the engine
jack
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Post by Shawki Shlemon on Oct 3, 2006 13:01:53 GMT
Simply put, energy can't be created or destroyed, just converted from one form to another . You can't get something for nothing .  |
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