Electrical – Unable to trigger 12V DC Stepper Motor without driver

I am trying to test a 12V stepper motor using just a 12V DC adapter without any driver, but I am unable to get it triggered. I am using Velleman's MOTS1 motor and as per the data sheet attaching the power's negative terminal to the red wire and the positive terminal one by one to the other four wires.

1). To eliminate the possibility of a faulty motor, I even tried with two different motors of the same model. But both motors did not work.

2). I also realized that the adapter is delivering 11.8V instead of exact 12V. So, to eliminate the possibility of lower voltage, I supplied 15V using batteries, but that too did not work.

3). Also, using the same adapter and battery sets, I am able to trigger other regular 12V DC motors.

So most probably, I am doing something wrong here specific to stepper motors.

Please help! Let me know if you need more information from me.

I am an absolute newbie electronics hobbyist and have just 3 months of basic theory and practical experience. So, I guess, every suggestion is helpful 🙂 .

Motors specifications from the Velleman's website – https://www.vellemanusa.com/products/view/?id=351245&country=us&lang=enu

• resistance: 280 ohm
• rated voltage: 12 Vdc
• current: 32 mA
• impedance: 380 ohm
• phase: 4
• step angle / step: 5.625° / 64
• reduction ratio: 1/64
• detent torque: 4.86 ozf.in
• pull-in torque: 4.17 ozf.in
• max. starting pulse rate: 550 pps
• max. slewing pulse rate: 90 pps
• temperature range: 77 °F
• noise: 40 dB
• cable: 420 mm AWG 1095#28
• terminal: JST SPH-002T-P0.5S
• insulation strength: AC 600 V – 1 sec. cut-off current: 10 mA
• colors:
  1. B1: pink
  2. A1: orange
  3. A2: yellow
  4. B2: blue
  5. GND: red
  6. GND2 (for MOTS2): brown

DC Adapter specifications:

• DC Volt Output: 12V
• DC Current: 2.5 A