How do you calculate rpm

So I have been trying to figure out how to calculate rpm to see what gearing would be the best for my drive. Does anyone know how to in a simple way or know a calculator I could use. Or maybe what two gears can create a certain rpm. This would be really helpful because I don’t have physical parts to test it with.

you simply multiply your motor speed by your gear ratio. so if you’re running a 7:1 flywheel on 600 rpm that’d be 600*(7/1)

3 Likes

And with this as well blue motors are 600rpm, green motors are 200rpm, and red motors are 100 rpm.

By any chance would any of you know how to calculate the loss of energy due to friction, in vex, such as transfer between a 1:1 gear ratio

No, because it depends on many factors, such as bearing usage, lubrication, and tightness of joints. An easy guideline, though, is to remember that the more gears you use, the more loss you will have due to friction, always.

4 Likes

Xenon27 I kind of understand that but how do you know the numbers for the 7:1 thing.I Have never understood that.

the different sized gears have ratios determined by the number of teeth. the gears are all multiples of 12 so you can simplify it like this:

12t gear : 1
36t gear : 3
60t gear: 5
84t gear: 7

11 Likes

Thank you. This will help out a lot

To look at it in a (kind of) un-simplified way, you just take the two gears you want to find the ratio of and put them into a fraction and simplify the fraction. So 12t and 60t would be 12/60 and that simplified is 1/5. Now although that would seem like a 1:5 ratio, it’s actually a 5:1 ratio, because if you are powering the 12t gear into the 60t gear, every time the 12t gear spins 5 times, the 60t gear spins once, hence the 5:1.

(If this was all too confusing, just listen to @Xenon27.))

4 Likes

Thank you for that to. I could use that but it is just a bit more work then Xenon27s way of doing it. But still helpful to look at it from different views

2 Likes