Low Or High Torque?

[circuitfish]

Hi all,

When it comes to stepper motors what are the advantages of using low torque over high torque? Does low torque use less power?

Any help would be much appreciated,
Steve

 

[crutschow]

Torque is related to the power output (power = torque x rpm), so obviously a higher torque motor is larger and requires more powerful electronics to drive it. Thus you don't want to over-specify the motor size for the load you are trying to drive, as with any electric motor. But, of course, you want a reasonable design margin (perhaps 50% over the anticipated load).

 

[circuitfish]

Right - so would a high torque motor draw more current?

Thanks.

 

[Ubergeek63]

Right - so would a high torque motor draw more current?

Thanks.

it will draw as much current as you feed it...

you are getting the right answer but to the wrong question. at any GIVEN speed and current, a high torque motor will have a higher torque.

conversely, at any GIVEN speed and torque, a high torque motor will take less current.

up to a point a stepper ALWAYS draws the same amount of current regardless of load or speed. beyond that point the current and torque start to decline.

At low speed a stepper coil is a RESISTOR. at high speeds you start to see the coil inductance reducing the current.

dan

 

[Hero999]

If you want to run it at a higher speed, you can use a higher voltage but you'll need to reduce the duty cycle at lower speeds.

 

[crutschow]

Right - so would a high torque motor draw more current?

Yes. A high torque stepper motor will require more current to generate its rated torque.