Calculating torque

[Paul-R]

I'm working on a design and while I can calculate the force for a magnet, I don't know how to calculate the torque that is generated.

Shafts have torque.

The torque on a shaft is the force that results, multiplied by the distance of that force from the centreline of that shaft.

http://en.wikipedia.org/wiki/Torque

Paul.

[Low-Q]

I have used a square magnet with the same area as your disc. I used a 1/2" x 2,6" x 2,6" iron piece 1mm apart. The force between them are 25N. If this force is placed 0.5 meters from the shaft, the torque is 12,5Nm. 1m from the shaft -> 25Nm.

If I increase the legth of the iron bar with 1 inch, the force increase to 62N.

Now you can calculate torque based on your construction.