High-Pitch Metal Screaming / Piercing Whine from Motor
Starting the vacuum emits an unbearable high-pitch metallic screech. Sound pitch varies with motor speed. Odor of heated metal may follow.
Possible Causes
Rotor bearing failure progression:
- Bearing Ball Spalling & Pitting: Sealed lubrication depleted by micro-humidity or age, causing dry metallic galling between balls and races.
- Unbalanced Separator Induced Runout: Running a dirty separator for prolonged periods accelerates radial bearing wear.
- Armature Shaft Fretting: Micro-movement between bearing inner ring and rotor journal.
Diagnostic & Check Steps
1. 立即停止使用，避免轴承彻底碎裂打烂电机转子；2. 卸下离心分离器确认是否积泥失衡；3. 送修专业服务中心拆除旧轴承、压装全新日本 NSK 高速双密封轴承并重做转子动平衡。