I've got a few newbie questions about how to read stepper specs. I found what may be a very good fit for a Kossel, and I don't quite understand what I'm reading. Here are the specs for the motor:
Frame Size: NEMA 17
Number of Lead Wires: 6
Lead Wire Configuration: flying leads, no connector
Lead Wire/Cable Length: 300 mm
Unipolar Holding Torque: 23 oz-in
Bipolar Holding Torque: 32 oz-in
Step Angle: 1.8 deg
Bipolar Series Current: 0.67 A/phase
Bipolar Series Resistance: 7.8 Ohms/phase
Bipolar Series Inductance: 11.2 mH/phase
Unipolar Current: 0.95 A/phase
Unipolar Resistance: 3.9 Ohms/phase
Unipolar Inductance: 2.8 mH/phase
Rotor Inertia: 5.38E-04 oz-in-sec2
Insulation Class: Class B (130 ºC)
Shaft Run Out: 0.002 inch T.I.R. max
Radial Play: 0.0008 inch max w/ 1.1 lb load
End Play: 0.003 inch max w/ 1.1 lb load
Perpendicularity: 0.003 inches
Concentricity: 0.003 inches
Rated Voltage: 3.71 V
I recall reading in this forum and on the wiki that inductance between 2-5 mH is ideal to ensure rapid acceleration. Unipolar Inductance is at the lower end of that range, which would make this motor pretty good. On the other hand, the Bipolar Series Inductance is way out of range for this application if that's the thing I should be concerned with.
So, my question: What's more important? The Unipolar Inductance or the Bipolar Series Inductance?
Thanks,
Uncle Sasquatch
Frame Size: NEMA 17
Number of Lead Wires: 6
Lead Wire Configuration: flying leads, no connector
Lead Wire/Cable Length: 300 mm
Unipolar Holding Torque: 23 oz-in
Bipolar Holding Torque: 32 oz-in
Step Angle: 1.8 deg
Bipolar Series Current: 0.67 A/phase
Bipolar Series Resistance: 7.8 Ohms/phase
Bipolar Series Inductance: 11.2 mH/phase
Unipolar Current: 0.95 A/phase
Unipolar Resistance: 3.9 Ohms/phase
Unipolar Inductance: 2.8 mH/phase
Rotor Inertia: 5.38E-04 oz-in-sec2
Insulation Class: Class B (130 ºC)
Shaft Run Out: 0.002 inch T.I.R. max
Radial Play: 0.0008 inch max w/ 1.1 lb load
End Play: 0.003 inch max w/ 1.1 lb load
Perpendicularity: 0.003 inches
Concentricity: 0.003 inches
Rated Voltage: 3.71 V
I recall reading in this forum and on the wiki that inductance between 2-5 mH is ideal to ensure rapid acceleration. Unipolar Inductance is at the lower end of that range, which would make this motor pretty good. On the other hand, the Bipolar Series Inductance is way out of range for this application if that's the thing I should be concerned with.
So, my question: What's more important? The Unipolar Inductance or the Bipolar Series Inductance?
Thanks,
Uncle Sasquatch