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# Gearing, Slowing the System

## Gearing, Slowing the System

(OP)
Hello,

I am aware that I can trade torque for RPM using gearing, however is there a way to slow down a high torque system with the resultant being a low torque high RPM system?
Example:
Suppose that I have a bucket of water hanging on a pulley from the ceiling of a room. The rope that is attached to the bucket of water is also attached to a wheel system that is on the ground. As the bucket of water falls, it will pull on the rope which will pull on the pulley and in turn spin the wheel.

Currently, once the bucket is released it will quickly drop and the wheel will spin really fast for a second and then stop.

My question is, is there a way to engineer the wheel system such that it makes the bucket fall slowly over time without loosing a significant portion of the stored potential energy?

Any help pointing me in the right direction would be most appreciated.
Thank you,
James :D

### RE: Gearing, Slowing the System

Use a counter weight.

### RE: Gearing, Slowing the System

The energy has to go somewhere. If the step-up ratio is too high it will be put into friction of the gears and turned into heat. An alternative is an escapement as is used in pendulum clocks.

### RE: Gearing, Slowing the System

(OP)
Thank you for the replies!

I like the idea of a counterweight, however, I'm not sure it will work. You are right that it will slow the main load down, however the main load's gravitational force will cause the system to have a high velocity overtime. So the load will start to move slowly at first, but after a little bit of time, it will be moving too fast. Thank you very much for your thoughts though :)

The pendulum idea sounds really neat! Although that will greatly increase the complexity of the system, it might be worth looking into. Outside of pendulum clocks, can you think of any other system that utilizes a similar regulating function? Thank you for your post. :)

### RE: Gearing, Slowing the System

First thing that comes to mind is a torque converter, or fluid coupling.

### RE: Gearing, Slowing the System

jlatshaw,

Would something like a centrifugal clutch work? You want something that engages if the speed gets too high.

--
JHG

### RE: Gearing, Slowing the System

Use the wheel system to wind a spring?

### RE: Gearing, Slowing the System

That is essentially describing the function of a torsion bar in a garage door.

When it comes to couplings we are always here to help.
WWW.PSCCOUPLINGS.COM

### RE: Gearing, Slowing the System

(OP)
Thank you all very much for the response that you have given me. I greatly appreciate them.

The torsion bar and pendulum ideas are my favorites. Thank you for taking time to help think of those :)

### RE: Gearing, Slowing the System

Depends where you want to put the energy.

If you want to convert the potential energy of the bucket into kinetic energy in the shaft (a flywheel for example), you need a variable ratio drive. eg use a deep pulley groove the same width as your cord so that the effective pulley diameter is large with the bucket at the top and small with the bucket at the bottom of its travel.

je suis charlie

### RE: Gearing, Slowing the System

what about a simple brake system? like disk brakes.

### RE: Gearing, Slowing the System

Is your actual system accelerated, as the falling bucket of your example?

"Engineering is achieving function while avoiding failure." - Henry Petroski

### RE: Gearing, Slowing the System

#### Quote:

is there a way to engineer the wheel system such that it makes the bucket fall slowly over time
YES

#### Quote:

without loosing a significant portion of the stored potential energy?
NO

See "over unity", "no free lunch", and "Atwood's Machine".

### RE: Gearing, Slowing the System

Mike.
Your "no" needs to be qualified.
The energy can be stored elsewhere eg it could be used to raise a counterweight, accelerate a flywheel or charge a battery or capacitor.

je suis charlie

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