What power supply needed?

Hello,

I have some trouble in finding the right power supply for my geared stepper motor. The datasheet of the stepper motor can be found here: http://yuzhou.com.br/loja/files/produtos/files/1_ak23r200f6fn18g20linix.pdf.

I want to use the bipolar (series) stepper motor;
current: 2.1 A/phase
Voltage: 3.4 V/phase

What I did find on the internet is;
For bipolar (series) stepper motors the current should be multiplied with sqrt(1/2) and the voltage with sqrt(2)...
But what specs should the power supply that I need have? I want to use it as full step stepper motor, so the specs of my power supply should be;
current: 1.5 A
Voltage: >5 V?
Or multiplied by some integer because there are more phases?

Furthermore, I bought the following driver: http://arduino.cc/documents/datasheets/L293D.pdf.
Yes I know, it is not compatible with this motor. The driver will blow up I guess. But what driver would I need? Same specs as the power supply?

Regards,
Harm

You can use one of these type of drivers (there's about 10 variations of this module around ebay):
http://www.ebay.com/itm/like/331141029475?lpid=82
or you can look for a proper stepper driver that can handle 2A/phase.
You might be able to find a dc to dc converter (buck converter) but it's going to take some looking to find one in that range.

@harmvd91: With a bipolar stepper (or any for that matter) it is not a voltage controlled device, it is current controlled. From your data sheet you can see the winding resistance is 140 milli-ohms! Almost zero. So if you want to power it from a (separate) 5V supply, you will need a resistor in series with each winding that limits the current to coincide with the motor's max current but more importantly with the DRIVER'S max current. Using the L298 is not much fun since it's good for only about 1A. If you're determined to use that, each winding will need 5 ohm resistors in series with it.

If you want to use a REAL Stepper drive, use one of these for increased performance and to do away with the current limit resistors. These have a "pot" to adjust the current and it's done via PWM. No, don't try to do PWM with the Arduino, you won't have CPU time to do anything else.

Thanks for the replies,

About those real stepper drivers.. They are not compatible with my Arduino MEGA??
And is there any driver which is compatable with my Arduino MEGA and can carry this current? (which means I would need to resistors I guess)

Regards,
Harm

rmetzner49:
@harmvd91: With a bipolar stepper (or any for that matter) it is not a voltage controlled device, it is current controlled. From your data sheet you can see the winding resistance is 140 milli-ohms! Almost zero.

No, 1.4 ohms. That motor cannot be driven at full power from any single-chip
driver which all max-out at 1.5A or so (certainly get difficult to cool), but the best
would be the DRV8825 I think.

An industrial controller (GeckoDrive is the cheapest range I think) is the ideal
solution, using MOSFET bridges. You would power from 24V or 26V at 1A or
thereabouts.

Clean off them glasses, Mark: The second to last value in each column is the winding resistance, 140 milliohms for bipolar and 70 for unipolar. Are we looking at the same data in the link the OP provided?

23
Bipolar – Série 300.0 15.0 2.1 3.4 140.0 8.0
Unipolar 200.0 10.0 3.0 2.4 70.0 2.0

rmetzner49:
@harmvd91: With a bipolar stepper (or any for that matter) it is not a voltage controlled device, it is current controlled. From your data sheet you can see the winding resistance is 140 milli-ohms! Almost zero. So if you want to power it from a (separate) 5V supply, you will need a resistor in series with each winding that limits the current to coincide with the motor's max current but more importantly with the DRIVER'S max current. Using the L298 is not much fun since it's good for only about 1A. If you're determined to use that, each winding will need 5 ohm resistors in series with it.

If you want to use a REAL Stepper drive, use one of these for increased performance and to do away with the current limit resistors. These have a "pot" to adjust the current and it's done via PWM. No, don't try to do PWM with the Arduino, you won't have CPU time to do anything else.

http://www.pololu.com/category/120/stepper-motor-drivers

One more question to you;
Would this driver: 'ST-M5045' be ok for my stepper motor?

Yes, either of those two will drive your motor without current limiting resistors. On the Pololu part, it uses the Allegro 4988 chip and has adjustable phase current. With the other one, you have jumpers to set phase current.

If you plan to use any stepper libraries, make sure you use one that has STEP and DIRECTION controlling output pins. Some libraries work by giving you the logic levels to energize the phases, which is what the L298 needs. Not what you want.

With either part, running the motor is child's play. Just pick an output for STEP, and set it HIGH, then LOW every time you want to take a step. Then use a var to keep track of counts. The function of the DIR pin is obvious, it changes the direction of rotation.