Does anybody know where I might be able to purchase a 1:350 (or around that ratio) gearbox? 1

[deanwalker101]

I am debating whether to purchase or designed a speed increasing gearbox that will power a generator from a water wheel. The water wheel is moving about 2 rpm and I need an output of 600 rpm to power a generator. Any ideas?

 

[drawoh]

deanwalker101,

How much torque do you need?

When you connect your drive to your waterwheel, the inertia of your generator's armature will be multiplied by the ratio squared, or around 100,000. This could result in some crazy stresses on the generator's shaft. You need to check for this in your calculations.

Mills with waterwheels all used to be belt driven. Why not use some belt drives? Three belts with a 7:1 ratio will have a total ratio of 343:1.

--
JHG

 

[deanwalker101]

drawoh,

You're absolutely right, a belt drive completely slipped over my head; and yes, I was looking to have 3 to 4 connections and space is crucial, so the 7:1 ratio sounds perfect. I'm going to be using mountable bearings with keyed shafts and a steel enclosure, and I want to minimalize the displacement of the system. Also quietness was a factor, so belts will definitely be a viable solution. I just needed to reach an rpm range of 500-650 to power a generator. Inertia shouldn't be a problem, as I've made necessary adjustments so that it won't effect the generator itself.

 

[Tmoose]

If by "mountable bearings" you mean commercial pillow blocks or flange bearings secured to the shaft with set screws or eccentric collars I predict that in a belt drive application in the not-too-distant future there is strong possibility you will likely see this -

http://www.hitekbalancing.com/blog/...shaft-and-bearing-repair-and-noise-reduction/

http://3.bp.blogspot.com/_8H0W-6Yoqp0/SUNBabOoBgI/AAAAAAAAAIE/Kx2hCoXzzxU/s1600/RotorShaftFail.jpg

nearly impossible to achieve (and assemble) shaft-to-bearing fits are the solution.
An alternative is this -

http://evolution.skf.com/us/concentra-–-a-novel-locking-concept/

http://www.youtube.com/watch?v=v_8W3IJGT_o

 

[tbuelna]

You still did not say what the torque levels are in your drivetrain. A 1kW generator at 600rpm would mean a torque at the 2rpm water wheel of over 3000 ft-lb. This level of torque is quite high for most belt drives. The radial loads on the bearings would also be quite substantial.