Reference acceptance criteria for stepper motors (translated from a Chinese enterprise standard). Use as a checklist during incoming / final inspection.
| # | Item | Requirement | Method / Equipment |
|---|---|---|---|
| 1 | Appearance | No obvious damage or rust; nameplate and lead markings correct; leads/connectors intact; end-cover riveted firmly to housing with no looseness. | Visual comparison with golden sample / drawing. |
| 2 | Dimensions | Overall and mounting dimensions conform to approved drawings; lead and terminal form correct. | Calibrated measuring tools (vernier caliper). |
| 3 | Dielectric strength | Windings to frame withstand AC 50 Hz, 500 V for 1 min with no breakdown/arc; leakage current ≤ 1 mA. | Withstand tester: ramp 0→500 V in ≥3 s, hold 1 min, ramp down. Set leakage at 1 mA. |
| 4 | Insulation resistance | Windings to frame ≥ 10 MΩ. | Withstand/insulation tester. |
| 5 | DC resistance | Each phase resistance conforms to drawing. | Stabilize ≥2 h, measure per phase with DMM. |
| 6 | Rotation direction | Viewed from shaft end, rotates in the direction required by the drawing. | Energize at rated voltage, no load. |
| 7 | Pull-in torque | At 400 Hz, pull-in torque meets drawing. (Component approval: add 5 mN·m.) | Rated voltage @400 Hz, preset pulses / step-loss check with load, measure max non-slipping torque at 3 rotor positions, both directions. |
| 8 | Detent torque | Detent torque meets drawing. (Component approval: add 5 mN·m.) | De-energized; torque disk until shaft begins continuous rotation; record max torque. |
| 9 | Running torque | Running torque meets drawing. (Component approval: add 5 mN·m.) | Rated voltage @100 Hz; measure max rotor torque. |
| 10 | Friction torque | Output / gear friction torque meets drawing. (Component approval: reduce range by 5 mN·m.) | Two phases energized, locked rotor; torque disk until shaft rotates continuously. |
| 11 | Temperature rise | Rated voltage, 100 Hz no-load: temperature rise < 40 K. | Measure R1@t1 (cold, ≥2 h) and R2@t2 (hot, ≥2 h); compute rise from resistance change. |
| 12 | Noise | No abnormal noise at no-load or rated load. | Run no-load and rated load; listen at 5 cm. |
| 13 | Shaft strength | Shaft withstands 19.6 N radial / axial pull / axial push, each 10 s, no deformation or damage. | Apply 19.6 N at 3 mm from shaft end, hold 10 s (each direction). |
| 14 | Lead strength | Each lead (motor end and plug end) withstands 9.8 N pull for 10 s, no break / insulation damage. | Apply 9.8 N vertically to each lead end, hold 10 s. |