The DG2039-037 miniature DC motor with integrated gearbox with 170 rpm rotational speed and 6V supply voltage. Ă? The diameter of the motor is 20 mm and the length is 39 mm. The motor has a shaft with a diameter of 2mm.The DG2039-037 miniature DC motor with integrated gearbox with 170 rpm rotational speed and 6V supply voltage. Ă? The diameter of the motor is 20 mm and the length is 39 mm. The motor has a shaft with a diameter of 2mm.