Obtaining maximum torque from a motor

[Mohamed Maher]

Hello,

I want to make an instrument that measures the torsion produced in a circular shaft. A motor will apply a torque on one end of the rod while the other end will be fixed. I will measure the twisted angle formed at free end and using this angle I can measure the torsion in the rod.

My question is that What type of motors I can use in my project to get torque around (100 - 150 Newton.m) and How can I get this maximum torque without the motor being burnt ??

Thanks in advance

 

[Gryd3]

Hello,

I want to make an instrument that measures the torsion produced in a circular shaft. A motor will apply a torque on one end of the rod while the other end will be fixed. I will measure the twisted angle formed at free end and using this angle I can measure the torsion in the rod.

My question is that What type of motors I can use in my project to get torque around (100 - 150 Newton.m) and How can I get this maximum torque without the motor being burnt ??

Thanks in advance

Probably the safest bet regardless of motor is to use some form of gearing.
This will allow you take take a relatively weak motor and produce a scary amount of torque. The trade-off will be reduction in speed.
You can find motors that are pre-attached to various gearing ratios, all you need to do is find one you want, or make one if you have access to some spare gears

 

[BobK]

Well, motors are designed to run continuously, not provide a little twist and stop. This is not a good use for a motor.

Why not use a lever arm and a weight to produce an accurate amount of torque?

To get 150 Nm you could use 150 / 9.8 = 16.3 Kg on a 1m lever arm.

If you absolutely must use a motor, a stepper motor (with proper gearing) would be the best kind to use. These are designed to have a "hold torque" when not moving.

Bob

 

[Minder]

Most motors exert the maximum torque at zero rpm, for a simple reading of this is the use a spring scale and pulley, the radius of the pulley and the display on the scale will give you the maximum torque in ft-lbs etc available at the motor continuous rated current.
If this is a fixed load and you require to know the break-away torque, either use the above method or a small torque wrench.
M.