Trouble getting 6 wire stepper running, monster moto shield

Hello all,
I was hoping someone could take a look at my setup and give me some help. This is my first project with electronics/arduino--I have a basic understanding of circuits and programming.

I have a monster moto shield (pair of VNH2SP30 full-bridge drivers), bipolar.
I also have a 6 wire stepper.
Links for both:

I am using this sample code:

/*************************************************************
Motor Shield Stepper Demo
by Randy Sarafan

For more information see:
http://www.instructables.com/id/Arduino-Motor-Shield-Tutorial/

*************************************************************/

int delaylegnth = 30;

void setup() {
  
  //establish motor direction toggle pins
  pinMode(12, OUTPUT); //CH A -- HIGH = forwards and LOW = backwards???
  pinMode(13, OUTPUT); //CH B -- HIGH = forwards and LOW = backwards???
  
  //establish motor brake pins
  pinMode(9, OUTPUT); //brake (disable) CH A
  pinMode(8, OUTPUT); //brake (disable) CH B


  
  
}

void loop(){
 
  digitalWrite(9, LOW);  //ENABLE CH A
  digitalWrite(8, HIGH); //DISABLE CH B

  digitalWrite(12, HIGH);   //Sets direction of CH A
  analogWrite(3, 255);   //Moves CH A
  
  delay(delaylegnth);
  
  digitalWrite(9, HIGH);  //DISABLE CH A
  digitalWrite(8, LOW); //ENABLE CH B

  digitalWrite(13, LOW);   //Sets direction of CH B
  analogWrite(11, 255);   //Moves CH B
  
  delay(delaylegnth);
  
  digitalWrite(9, LOW);  //ENABLE CH A
  digitalWrite(8, HIGH); //DISABLE CH B

  digitalWrite(12, LOW);   //Sets direction of CH A
  analogWrite(3, 255);   //Moves CH A
  
  delay(delaylegnth);
    
  digitalWrite(9, HIGH);  //DISABLE CH A
  digitalWrite(8, LOW); //ENABLE CH B

  digitalWrite(13, HIGH);   //Sets direction of CH B
  analogWrite(11, 255);   //Moves CH B
  
  delay(delaylegnth);

}

I THINK my problems are in the wiring. I am using a 9V power supply, supplied to motor board only at + and - terminals, and connect these pins from the arduino to the motor board: 3, 11, 9, 8, 12, 13. The arduino is powered via usb during the program. I'm waiting on soldering gun + solder, hence the individual connections. If there are no other obvious problems, it is totally possible that my crappy hook + electrical tape connections just aren't quite doing the trick. Advice/suggestions?

You absolutely must use screw-terminals, spade-terminals or soldered connections for high current motors - these are highly inductive
loads, any intermittency in connections will cause sparking and possibly damage to semiconductors from voltage spikes. For the
same reason you must never unplug a powered-up stepper motor.

Your motor needs a chopper-drive circuit really - its bipolar with low-resistance windings (don't know why it has 6 wires,
you really would not drive this motor unipolar!).

The windings are 3V but those H-bridges don't work below 5.5V, this is rather tricky (you will need PWM to avoid overloading
the motor).

9V supply? You don't say how many amps it provides... From 9V you'll need something like 33% PWM waveform max (but you'll need to
wire in an ammeter to check this.

How fast do you need the motor to turn?

MarkT:
You absolutely must use screw-terminals, spade-terminals or soldered connections for high current motors - these are highly inductive
loads, any intermittency in connections will cause sparking and possibly damage to semiconductors from voltage spikes. For the
same reason you must never unplug a powered-up stepper motor.

Your motor needs a chopper-drive circuit really - its bipolar with low-resistance windings (don't know why it has 6 wires,
you really would not drive this motor unipolar!).

The windings are 3V but those H-bridges don't work below 5.5V, this is rather tricky (you will need PWM to avoid overloading
the motor).

9V supply? You don't say how many amps it provides... From 9V you'll need something like 33% PWM waveform max (but you'll need to
wire in an ammeter to check this.

How fast do you need the motor to turn?

Ok. I will definitely not try to run this again without proper connections. It seemed to me that the 'rated voltage' wasn't too serious, and that you should try to go around 3 times higher so that you are working with lower current. The power supply I purchased (link below) provides 600 mA. I don't completely understand the PWM waveform stuff (does it enter into the programming? Didn't seem to in any of the sample programs). Multimeter coming in with the headers and sauder :slight_smile:

Preferably higher torque and slower speed (seems that I can specify that in choice of wires), though it really doesn't matter. The design requires some gears to transmit the torque over anyway, so rpm is pretty negotiable. I should also mention that I never got the motor to run, at all. Not even a kick.

If you run a stepper motor at 3 times its rated current and voltage then you are
running at 9 times its rated power. These devices are often thermally limited - the
design power is that which raises the temperature by perhaps 50 to 80 deg C. 9 times
as much power would destroy the motor in a few minutes.

Older designs of stepper motor used less robust permanent magnets than today’s
NdFeB one’s and over-current could de-magnetise the rotor, not just overheat the motor.

The same older designs cannot be disassembled because just opening up the magnetic
circuit would substantially demagnetise the permanent magnets!

Rated current for the motor is 2, rated voltage 3, so max power for motor is 6. That power supply gives 0.6A and 9V, so 5.4 W is given power. Shouldn't this work alright? And you mentioned I should have a chopper driver for that motor, this is just the 'i don't know what the heck I'm doing, lets buy some parts and tinker' prototype (wish I'd picked a less-ridiculous/expensive shield), but I'm thinking it should still run(?). We'll probably end up going with the adafruit shield with a bipolar or unipolar stepper (non hybrid).

You mentioned that you wouldn't want to drive this motor in unipolar--why is that? Also, while I was shopping around I noticed that it is uncommon to find larger bipolar motors, and they seem to require more power to do less! For example, the unipolar one I bought works with 6 watts, this bipolar one (link below) works with 5, yet the unipolar one had almost 10x the listed torque! What the heck? Everything I've read says the bipolar motor should be way more powerful!

http://www.robotshop.com/ca/productinfo.aspx?pc=RB-Soy-22&lang=en-US

The headers and soldering gun is in, looks like I should be able to get it all hooked up today! Thanks for your help MarkT, but I'm still a little confused on whether I should even plug this guy in now. Is 5.4 given power ok when max is 6, and will this work (ie run for a couple minutes for proof of concept), or am I frying the motor?

Also, since I've got an external supply, I just trim the Vin (and only the Vin) pin, correct?