Balancing Machine
AutomatedSemi-automatic
Measures and corrects rotor unbalance (material removal or addition).
✓ Expert reviewed All content on this page has been reviewed by a senior motor engineer.
Selection criteria
Minimum achievable residual unbalance, balance grade (e.g. G2.5 / G6.3).
Supply chain
Guangzhou, Dongguan and Shenzhen have makers of rotor balancing machines for small motors, and Shanghai balancer makers run Guangzhou offices. Check the minimum achievable residual unbalance, correction method (drill, mill or add mass) and cycle time.
Buyer FAQ
- Which balance grade do small motors need?
- ISO 21940-11 (formerly ISO 1940-1) grades: G6.3 for general industrial motors, G2.5 for fans, pumps and higher-speed motors, G1 for spindles and precision drives. Convert the grade to a permissible residual unbalance in g·mm for your rotor mass and maximum speed.
- Single-plane or two-plane balancing?
- Short, disc-like rotors (outer-rotor cups, fans) can often be balanced in one plane. Rotors longer than about their diameter need two-plane (dynamic) balancing to correct couple unbalance.
- How is the correction made?
- Drilling or milling the rotor core or end ring is most common; adding balancing putty or weights is used on cups and fan hubs. Automatic machines measure, correct and re-check in one cycle.
Where it is used
Motor assembly process
- 57 mm Inner-rotor BLDC Motor9. Rotor balancing
- 37 mm Brushed DC Gear Motor (spur gearbox)7. Armature balancing
- 86 mm Two-phase Hybrid Stepper Motor (NEMA 34)9. Rotor balancing
- 57 mm Integrated BLDC Motor (built-in driver)9. Rotor balancing
- 70 mm Outer-rotor BLDC Motor10. Rotor balancing
- AC Servo Motor (60–130 mm flange)10. Rotor balancing
- Coreless Brushed DC Motor (16–22 mm)6. Rotor balancing
- IEC Three-phase Induction Motor (frames 80–160, IE3)4. Rotor balancing