MOTOR DRIVER ADIVSER

Using Arduino Motors, Mechanics, Power and CNC
1

Hello, I have been scouring the internet for some basic information about motor drivers. I'm in a bit of a mess and I'm in need of a 'motor driver adviser'. Someone who can point me to the parts I need. :slight_smile:

My project is to build a rig that propels a flatbed scanner along two axis. It's intended use is to make reproduction of artworks. The scanner will be mounted on a linear actuator not dissimilar to a CNC router.

The motor will drive a timing belt. The motor I have bought is a NEMA 23. its 76mm long and has the following specs:

STEP ANGLE: 1.8
CURRENT: 2.8A
PHASE RESISTANCE: 1.13?
PHASE INDUCTANCE: 3.6mH

You can view the data sheet here:
http://www.ebay.co.uk/itm/290593849218?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649#ht_4488wt_954

I will be using the Arduino BT as a controller. For simplicity sake, I decided on a plug-and-play approach. I bought the Arduino R3 Motor Shield whose specs are as follows:

Operating Voltage 5V to 12V
Motor controller L298P, Drives 2 DC motors or 1 stepper motor
Max current 2A per channel or 4A max (with external power supply)
Current sensing 1.65V/A
http://www.ebay.co.uk/itm/290593849218?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649#ht_4488wt_954

I have my doubts as to whether this can shield can handle my motor. My NEMA 23 has a rated current of 2.8A, the R3 Motor Shield supports up to 2A per channel or 4A max. I would appreciate it if someone could clarify whether or not this is a suitable driver and if so, how I would go about using it to provide its maximum current of 4A.

Failing this I shall have to look into using a motor driver with a separate power supply. I live in London so any UK suppliers would be appreciated. Can anyone recommend a suitable motor driver?

I look forward to hearing your thoughts and thankyou in advance for your time.

Best, Arthur

2

That's a high-performance stepper designed for high speed, and would match a constant-current switch-mode driver like the A4983, A4988 -
Pololu - A4988 Stepper Motor Driver Carrier. The L298 isn't a constant current driver - this means that to avoid overheating/overloading the motor at low speeds you'll have to use a supply voltage that can't drive it very fast (this may not be an issue to you though).

Also the L298 isn't efficient at low voltages since its got Darlington outputs...

3

To be clear, am I wasting my time with the R3 Motor Shield?

Best, Arthur

4

any suggestions would be greatly appreciated. I am looking for a simple solution with sufficient documentation surrounding the driver to make the programming/wiring easy - I do not have a background in robotics!! :cold_sweat:

5

Well the motor wants 3V 2.8A and if the L298 is given a 5V supply it will drop about 2V in its output transistors, giving the 3V for the motor - but you'll be taking it over its current limit - so it doesn't look good.

You can't run the L298 motor supply less than 5V either, it has to be at or above the logic supply level... In fact it might be 7V, datasheet is a bit unclear.

6

ok so scratch the idea of using the motor shield. how does this seem instead:

1 Axis DC12-24V 3.5A Adjust TB6560 CNC Stepper Motor Driver Control Board Module
http://www.ebay.co.uk/itm/1-Axis-DC12-24V-3-5A-Adjust-TB6560-CNC-Stepper-Motor-Driver-Control-Board-Module-/300672369966?pt=UK_BOI_Industrial_Automation_Control_ET&hash=item460178452e#ht_4178wt_954

Specifications:

Rated voltage: DC 12V-24V
Maximum current: 3.5A
Current adjustable (Current Settings): 0.5A, 1A, 1.5A, 1.8A, 2A.2.5A, 3.5A
Subdivision adjustable (Excitation Mode): 1,2,8,16

Do you reckon it will work?