How to Decode Chinese Motor Part Numbers (57BL, 86BYG, JGB37-520, 5IK40GN, 80ST, YE3)

Why the codes look alike across factories

Most Chinese motor families grew from shared national standards and early state-factory catalogues, so thousands of makers still use the same building blocks: the frame size first, then letters for the motor type, then length, power or winding codes. Knowing the pattern lets you compare quotes from different factories and spot the closest standard model to ask for.

Stepper motors: 57BYGH56-401A, 35BY48

• 57 — frame size in mm (42 = NEMA 17, 57 = NEMA 23, 86 = NEMA 34).
• BYG — hybrid stepper; H usually marks the high-torque hybrid type. BY alone is a permanent-magnet (can-stack) stepper; BYJ is a geared one.
• 56 — body length in mm; the suffix (401A) is a lead-count and current/winding code that differs by maker.

BLDC motors: 57BL55-230

• 57 — frame size in mm; BL — brushless DC. Extra letters are series codes (for example S for square, F for flange, X for sensorless).
• 55 — usually body length in mm; the suffix is a voltage, speed or winding code.

DC and gear motors: 60ZYT, JGB37-520, 555

• ZY / ZYT — permanent-magnet brushed DC motor (直流永磁); the number in front is the housing diameter in mm.
• JG — micro gear motor; the letter after it is the gearbox style (Y = worm); 37 is the gearbox diameter; 520 is the motor size code.
• 130 / 370 / 385 / 555 / 775 — standard can-size codes for small brushed motors; a larger number means a larger motor (555 is about 36 mm in diameter, 775 about 42 mm).

Small AC gear motors: 5IK40GN-CF

• 5 — frame: 2 = 60 mm, 3 = 70 mm, 4 = 80 mm, 5 = 90 mm, 6 = 104 mm square.
• IK — induction (constant speed); RK — reversible; TK — torque motor. 40 — output in watts.
• GN / GU — pinion shaft for the matching gearhead (A = round shaft). C — single-phase 220 V (A = 110 V, S/T = three-phase 380 V); F — cooling fan. The gearhead is coded separately, e.g. 5GN50K for 1:50.

AC servo motors: 80ST-M02430

• 80 — flange size in mm; ST — AC permanent-magnet servo (a series code shared by many Chinese makers).
• 024 — rated torque 2.4 N·m; 30 — rated speed 3000 rpm. So 130ST-M10015 is 10 N·m at 1500 rpm, about 1.5 kW. Brand-name servos (Inovance, Leadshine, Kinco) use their own codes.

Induction motors: YE3-112M-4, YC90L-4, YY712-4

• Y — induction motor; E3 — efficiency class IE3 (GB 18613 grade 3). YVF / YVP are inverter-duty; YS is a small three-phase motor; YC, YY and YL are single-phase capacitor-start, capacitor-run and dual-capacitor motors.
• 112 — shaft centre height in mm (the IEC frame number); M — frame length (S short, M medium, L long), sometimes followed by a core-length digit; 4 — poles (about 1500 rpm at 50 Hz).