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What's the formula for planet RPM in an epicyclic gear.

What's the formula for planet RPM in an epicyclic gear.

What's the formula for planet RPM in an epicyclic gear.

(OP)
Hello,

I'm designing a planet gear with an output of 4:1. Here are the details; Sun = 24 teeth, Planet = 24 teeth, Ring = 72 teeth. The sun is the input, planet carrier is the output. My question is what is the formula for finding the output of the planets gears themselves? For example, for every 4 revoltions of the sun I will get 1 revolution of the planet carrier arm, but how many revolutions will I get from the planet gear itself?

RE: What's the formula for planet RPM in an epicyclic gear.

Overall ratio = (72+24)/24 = 4:1.
Assembly = (72+24)/N where N = number of planets, so ok for 3 or 4 planets.

RPM of planet gear relative to carrier =(-Zr/Zp) or -3, where Z is teeth and n is rpm. Relative to ground is (1-Zr/Zp), or -2.  

RE: What's the formula for planet RPM in an epicyclic gear.

(OP)
Thank you, exactly what I needed. Simulation works perfectly.

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