Speed and torque using lab view

[mikealder]

I used a couple of these when I did something similar quite a few years ago, long before Labview had been invented!

http://meccanoman.co.uk/catalog/product_info.php?cPath=83_84&products_id=2202

Mike

[Quincie]

Thanks mike.

[AnalogKid2DigitalMan]

There are also devices known as eddy current brakes or loads that can vary the load applied to a motor based on winding voltage or current that are commonly used in dynos and motor test systems. The name "Magtrol" comes to mind.

-AK2DM

[Wayne.C]

You really haven't said just how big or small your motor is.  The torque/RPM ranges you need to work in will ultimately determine which type of brake to use.  Eddy current brakes don't typically work well with small motors because of the high inertial load and the resulting high starting torques required of the motor under test.  Hysterisis brakes from Magtrol have much lower inertias.  You can also use a servo motor/drive combination to create a true 4 quadrant test.  This type of scheme often uses a water cooled braking resistor to disipate generated power.  Some of the newer systems actually put power back on the grid to increase overall efficiency of the testing process.