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General Misc => Misc => Topic started by: ltmhall on November 30, 2006, 09:03:28 PM

Title: speed related to torque
Post by: ltmhall on November 30, 2006, 09:03:28 PM

How is speed of a dc motor related to torque.

Title: Re: speed related to torque
Post by: Kohanbash on November 30, 2006, 09:22:48 PM

torque is inversely proportional to the speed.
the motor's data sheet usually has a torque/speed graph.

Title: Re: speed related to torque
Post by: JesseWelling on November 30, 2006, 11:43:14 PM

any body have any idea about voltage/amperage to speed/tourqe.
I know that a motor uses more amps to use more tourqe but... any thing else we should know?

Title: Re: speed related to torque
Post by: Kohanbash on December 01, 2006, 07:08:07 AM

just some useful stuff:

voltage is proportional to speed
torque is proportional to the armature current
torque is proportional to (output power/speed)
Horsepower=(torque * speed)/5252
also there are series, shunt, and compound DC motors. each have slightly different characteristics. for example: series motors have better start up torque and shunt has better torque vs speed characteristics.

Title: Re: speed related to torque
Post by: JesseWelling on December 01, 2006, 10:08:06 AM

brushless? ???

Title: Re: speed related to torque
Post by: Kohanbash on December 01, 2006, 01:40:49 PM

Those are all for brushed motors.

Someone please correct me if I'm wrong but i think brushless motors behave similar to AC motors since a higher current= higher torque and more current modulated pulses = greater speed. They also have a better power efficiency than Brushed DC motors.

Title: Re: speed related to torque
Post by: Admin on December 01, 2006, 01:42:19 PM

brushless motors require a controller . . . probably closer to a stepper? havnt actually used one . . .

Title: Re: speed related to torque
Post by: JesseWelling on December 01, 2006, 02:06:57 PM

I'm using this system on my r/c project car.
http://www.castlecreations.com/products/mamba.html
not for speed but more for efficiency.