controlling 3.1 volt steppers with adafruit motorshields v 2.3

Question

Hi.

I'm quite new to electronics and robotics.

I've got two adafruit motor shields and three steppers. The steppers has a rated current of 2.5 A and a phase resistance of 1.25 ohms.

I understand from adafruits documentation that it can control motors in a voltage range of 5-12 V dc.

My question is can I use my 3.125 V motors if I put a 3.55 Ohm resistor in serie in each phase of each motor?

I calculated the restistance using Ohm's law:

U = I * R

12 V = 2.5 A * (1.25 Ohm + 3.55 Ohm)

Have a nice Weekend

- Roar

Robert Peter Oakes · Accepted Answer

In most stepper motor controllers (Modern ones), you do not limit the voltage by setting up a divider (R1, R2 ) as they manage the pulse width in the same way as driving an LED with PWM, it is more about the current going through the Motor, its inductance will limit this automatically and is often set-up in the configuration of the controller So having a motor with only 1.25Ohms DC resistance means nothing to a pulse, its inductive reactance is what will matter and that to a pulse can be much higher than the DC Ohms It would be common to see a stepper like this having say a 12V supply but still driven directly from the controller with no additional limiting resistors, you can often have a current sense resistor that provides feedback to the controller so it can manage the average current / power through the motor

clem57 · Answer

Why did you pick the Max voltage in the range? Why not average? You really need to show schematic first to see the total picture. Clem

dmaruska · Answer

Wattage wise that is one large resistor >22W.

controlling 3.1 volt steppers with adafruit motorshields v 2.3

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