This is high precision bipolar Nema 17 stepper motor with 0.9 deg. step angle (400 steps/revolution). <br />Each phase draws current 1.68A, allowing for a holding torque of 44Ncm(62.3oz.in). <br /> <br /> <b>Electrical Specification:</b> <br /> <br /> * Manufacturer Part Number: 17HM19-1684S <br />* Motor Type: Bipolar Stepper <br />* Step Angle: 0.9 deg. <br />* Holding Torque: 44Ncm(62.3oz.in) <br />* Rated Current/phase: 1.68A <br />* Phase Resistance: 1.65ohms <br />* Inductance: 4.1mH+/-20%(1KHz) <br /> <br /> <b>Physical Specification:</b> <br /> <br /> * Frame Size: 42 x 42mm <br />* Body Length: 47mm <br />* Shaft Diameter: 5mm <br />* Shaft Length: 20mm <br />* D-cut Length: 15mm <br />* Number of Leads: 4 <br />* Lead Length: 500mm <br />* Weight: 370g <br /> <br /> <b>Connection:</b> <br /> <br /> Black(A+), Green(A-), Red(B+), Blue(B-) <br /> <br /> <b>Warning:</b> <br /> <br /> Make sure the motor connect to a constant current or chopper drive controller before you test motor. <br />Connecting the motor directly to a power supply will destroy the motor.