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# Physics/Flywheel calculation for 100w turbine

Question
QUESTION: Sir i have a 100w turbine 3000rpm 120v
for this i want to install flywheel i know about flywheel but not more calculation rpm power watt
so provide a formula for calculation of flywheel and at what rpm i have to rotate that flywheel
if flywheel size is 5"inch and weight is 850gm pulley shape....

ANSWER: I don't know anything about the amount of energy you want to store in the flywheel, how much power you want out of the wheel itself (the full 100W of the turbine, or something else?), or if you have some minimum rpm requirements for the flywheel.  RPM and the size/mass of the wheel don't equate to power at all.  For power I need to know the rate at which the RPM changes for the flywheel.  Can you please restate your question in a way that's possible to answer?  There's not enough physical information here.

---------- FOLLOW-UP ----------

QUESTION: Sir i want full 110w from flywheel
now can u say me that @ which exact rpm i will rotatate that flywheel so that it provide full 110w
and what exact weight of flywheel i used
provide a simple formula for this....

There's no exact rpm.  It depends on the rate of change of energy in the wheel.  You said 0.85kg and 6.35cm radius (I translated).  Your turbine is running at 3000rpm, meaning that if the flywheel runs in the simplest configuration it's turning at the same speed and will have 1/2(Iw^2) of energy = 81.8 Joules of energy.  That's with no gear box to alter speeds.  That could supply you with 110W for 81.8J/110W= 0.75 seconds, in theory.  To provide smooth power, you need a gearing mechanism and you should refer to an engineer.  For longer times, you'd need either higher speeds or a bigger wheel.  These are engineering choices, there is no one simple formula.  You create a design, then apply simple formulas to allow you to adjust the design until the design fits the needs.  It's a staged process, not a one-step thing.  I would consult an engineer and not a physicist, for further details.

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#### Dr. Stephen O. Nelson

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