Hi, I was actually making a rubik's cube solver and I have never used a stepper motor before and I was playing around with a 40 N-cm stepper motor( specifications attached) (I only need like 2.5 N-cm limiting torque) I bought it on eBay and it was specified as 12 volt (that would be 12/(2.5ohm)=4.8 amp) stepper motor on the eBay ad However the specification sheet says that it requires 3.25 volts only( that refers to 1.3 amp current).
So my questions are:
can a 1.3 amps enough to run the motor properly or do I need to use 12 volt power supply, also can an easy driver provide that amount of current.
If I have to use 3.25 volts, can I just use the 3.3 volt output from arduino?
I want the motor to gain maximum speed in short amount of time (as it need to rotate 90 or 180 degree and then stop). It works fine when I use delay of 200 microseconds at 3.3 volts and starts vibrating at lower delays, if I increase voltage to 12 volts, will it help me use shorter delays.
Can I decrease step size as it is 3600 with easydriver and I only need it to rotate 90 or 180 degrees. This way I won't have to worry about delays after each pulse.
When you are considering a product (such as an Easydriver) you need to read the specifications. The Easydriver has a max current of 750mA IIRC. The BigEasydriver (with the A4988 driver chip) can handle up to 2A in theory so it should be suitable for your 1.3A motor.
Stepper motors work best with high voltages. I would consider 12v the minimum for that motor. You can adjust the maximum current on the driver board to a lower level than 1.3A if you want to reduce the max torque - but you will need to experiment to see how effective that is.
The stepper driver board will also have upper and lower voltage limits that must be complied with.
Have a look at the examples in this Simple Stepper Code - the second example does not use delay().
jaskiratubhi:
Hi, I was actually making a rubik's cube solver and I have never used a stepper motor before and I was playing around with a 40 N-cm stepper motor( specifications attached) (I only need like 2.5 N-cm limiting torque) I bought it on eBay and it was specified as 12 volt (that would be 12/(2.5ohm)=4.8 amp) stepper motor on the eBay ad However the specification sheet says that it requires 3.25 volts only( that refers to 1.3 amp current).
Stepper motors like this don't have a voltage rating, they are current driven. This kind of motor
might be run from a 48V supply and a chopper driver circuit, in order to get good top speed.
Its a 1.3A, 2.5ohm bipolar stepper with 5mH of winding inductance - those low resistance and
inductance values mean a fast motor. The back-EMF when the motor spins can be much larger than
the norminal 3.2V across the winding when stationary.
So my questions are:
can a 1.3 amps enough to run the motor properly or do I need to use 12 volt power supply, also can an easy driver provide that amount of current.
It needs a current driver of 1.3A for maximum performance. Voltage depends on the top speed you
want. (And this can be a matter of some experimentation, beware). Try 12V, if you need more speed
go to 24V, etc etc.
If I have to use 3.25 volts, can I just use the 3.3 volt output from arduino?
Absolutely not. See above and note the 1.3A per winding rating - the Arduino 3.3 supply is
completely unable to provide that level of current and you should not be powering a motor
from a logic supply.
I want the motor to gain maximum speed in short amount of time (as it need to rotate 90 or 180 degree and then stop). It works fine when I use delay of 200 microseconds at 3.3 volts and starts vibrating at lower delays, if I increase voltage to 12 volts, will it help me use shorter delays.
You have to ramp the speed, as in the AccelStepper library to get anywhere near top speed.
Can I decrease step size as it is 3600 with easydriver and I only need it to rotate 90 or 180 degrees. This way I won't have to worry about delays after each pulse.
In the terminology you are asking whether to use microsteps, and yes you should, try 8x or 16x initially
and see what gives the smoothest performance. Full stepping generates lots of vibaration and causes
mis-stepping much more readily.