1. Essential influencing variables on rolling bearing noise • Bearing noise direct after installation (without regreasing) • damaged bearing (e.g. motor transportation/storage, coupling/bulley assembly, bearing assembly, bearing manufacturing) • bearing fit out of tolerance (rotor/end shield manufacturing) • poor lubrication (e.g. humidity, vibration, long time til motor installation / insufficient storage, transportation) • operating conditions / vibration excitation (e.g. caused by alignment, foundation resonance, belt, driven machine) • shrill bearing cage noise during first hours/days (matching/smoothening of bearing parts; especially roller bearings) • Bearing noise after longer operation (inclusive regreasing) • damaged bearing (e.g. wear, sliding marks, standstill marks, material fractures) • poor lubrication (e.g. aged grease, too late relubrication; wrong grease amount; unsuitable grease type) • operating conditions (e.g. thermal, vibration, bearing load, bearing current, enviroment, humidity) • shrill bearing noise after relubrication (less radial clearance caused by higher churning energy/temperature) Bearing noise (anti-friction bearing)