1. Bearing type and rotational speed
- Low and medium speed motors (e.g., <3000 rpm): Standard lithium soap greases are sufficient.
-
High speed motors (>3000 rpm, especially 10,000 rpm and above):
- Low viscosity, synthetic-based greases are preferred (PAO or ester-based).
- Grease with an NLGI consistency of 1–2 or softer (0–1) if necessary, should be used.
2. Temperature and thermal resistance
- Motor bearings heat up during operation.
- When selecting grease, the maximum operating temperature should be based on the estimated bearing temperature.
- General purpose motors: Greases resistant to 120–150 °C
- High temperature motors: Synthetic greases resistant to 150–200 °C
3. Electrical insulation (especially in inverter motors)
- In inverter-controlled motors, electrostatic discharge (EDM) or electric current can pass through the bearing.
- In this case, greases with low electrical conductivity (e.g., PFPE-based) are preferred.
4. Grease quantity and application
- Too much grease causes the motor to overheat, while too little grease results in insufficient lubrication.
- General rule: Fill 30–50% of the bearing's free space with grease.
- For high speeds, regular lubrication or centralized lubrication systems are recommended.
5. Typical selection criteria
| Feature | Recommendation |
|---|---|
| Base oil | Mineral or synthetic (synthetic for high speed and temperature) |
| Thickener | Lithium soap, Lithium complex, Aluminum complex |
| NLGI | 1–2 (high speed: 0–1) |
| Temperature resistance | 120–200 °C (depending on motor type) |
| Additives | Anti-wear, antioxidant |
| Electrical insulation | Requires low conductivity in inverter motors |
Please contact us for technical support on solutions suitable for your business.
