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Mechanical free energy devices => mechanic => Topic started by: solinear on June 27, 2009, 03:45:59 PM

Title: Calculating torque
Post by: solinear on June 27, 2009, 03:45:59 PM
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.  Can anyone help me with the calculation of torque generated by a 3"x1/8" N42 disc magnet that is 1mm from an iron bar (N42 magnet = 3075 surface gauss)?

Thanks
Title: Re: Calculating torque
Post by: robbie47 on June 27, 2009, 03:50:29 PM
Quote from: solinear on June 27, 2009, 03:45:59 PM
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.  Can anyone help me with the calculation of torque generated by a 3"x1/8" N42 disc magnet that is 1mm from an iron bar (N42 magnet = 3075 surface gauss)?

Can be done using FEMM simulation.
There are lots of different types of iron though....

If you let me know the dimensions of the iron I might be able to help you out.
Title: Re: Calculating torque
Post by: solinear on June 27, 2009, 03:54:03 PM
1/2" diameter, 3" long.  Just going to use a bolt for this.
Title: Re: Calculating torque
Post by: Low-Q on June 29, 2009, 03:34:59 AM
The torque is also detemined by where in the radius of the wheel you put the magnetic setup. Because torque is usually a force that is measured 1 meter from center of a wheel, you must find the force first, and then use the radius to calculate the force at 1 meter from center, there you have torque. Use FEMM. It works pretty good. Need help with it, just let us know.

Iguess the magnet has a 3rd dimention also, not only 3"x1/8" (We need to know Width x Hight x Depth of the magnet).

Vidar
Title: Re: Calculating torque
Post by: solinear on June 29, 2009, 04:20:27 AM
Height and width are the same.  Disc magnet (one dimension is a circle, in this case, the 3", which is also the pole).  The 1/8" is the depth.
Title: Re: Calculating torque
Post by: Paul-R on June 29, 2009, 04:30:34 AM
Quote from: solinear on June 27, 2009, 03:45:59 PM
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.
Title: Re: Calculating torque
Post by: Low-Q on June 29, 2009, 07:09:42 AM
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.