1. Why is the oil level crucial?
Low oil level (most dangerous situation):
Oil film breakage: The oil ring (or oil slinger) cannot be immersed in the oil deep enough, resulting in insufficient oil carryover. Without the separation of the lubricating oil film between the bearing and the shaft, dry friction occurs. This generates high temperatures within seconds, causing the Babbitt metal bearing to melt (bearing failure), and the rotor may seize, causing serious equipment accidents.
Heat dissipation failure: Lubricating oil not only lubricates but also cools. When there is insufficient oil, the heat generated by friction cannot be dissipated, and the accumulated heat will quickly damage the bearing.
High oil level:
Oil overflow and leakage: When the rotor rotates at high speed, an excessively high oil level will cause increased internal oil pressure, making it easy for lubricating oil to leak from the shaft end seal, polluting the environment.
Increased temperature rise (stirring loss): Over-immersion of rotating parts (such as oil rings and journals) in lubricating oil will generate huge stirring resistance. This will lead to additional power loss and abnormally high oil temperature, accelerating oil oxidation and deterioration.
Gas retention: Excessively high oil levels may affect the ventilation of the return oil pipe, causing pressure fluctuations within the tank and affecting the normal oil ejection of the oil ring.
2. What is the Ideal State?
For forced lubrication systems using oil rings (oil pans) to carry oil, the ideal state is not a fixed scale, but rather refers to the range of oil levels where the oil ring can efficiently and stably carry oil during dynamic operation, resulting in the lowest bearing temperature. It typically follows these principles:
Static State (Reference): When the motor is stopped, the oil level is usually adjusted to the center line of the oil level gauge. This is the reference point for adjustment.
Operating State (Critical):
Oil Ring Carrying Point: Ideally, when the rotor rotates, the lower part of the oil ring should be immersed in the oil to a depth of 10mm to 25mm (or 1/4 to 1/2 of the oil ring diameter). This ensures maximum efficiency in oil adhesion without excessive agitation due to deep immersion.
Dynamic Oil Level Changes: During operation, the oil level in the bearing housing will drop slightly (typically 5-10mm) due to oil agitation and some oil remaining in the circulation lines.
Ideal result: The oil level during operation should be maintained slightly above the middle position in the sight glass. At this point, the oil temperature is stable, there is no abnormal vibration, and there is no oil leakage at the shaft seal.
2. What is the Ideal State?
For forced lubrication systems using oil rings (oil pans) to carry oil, the ideal state is not a fixed scale, but rather refers to the range of oil levels where the oil ring can efficiently and stably carry oil during dynamic operation, resulting in the lowest bearing temperature. It typically follows these principles:
Static State (Reference): When the motor is stopped, the oil level is usually adjusted to the center line of the oil level gauge. This is the reference point for adjustment.
Operating State (Critical):
Oil Ring Carrying Point: Ideally, when the rotor rotates, the lower part of the oil ring should be immersed in the oil to a depth of 10mm to 25mm (or 1/4 to 1/2 of the oil ring diameter). This ensures maximum efficiency in oil adhesion without excessive agitation due to deep immersion.
Dynamic Oil Level Changes: During operation, the oil level in the bearing housing will drop slightly (typically 5-10mm) due to oil agitation and some oil remaining in the circulation lines.
Ideal result: The oil level during operation should be maintained slightly above the middle position in the sight glass. At this point, the oil temperature is stable, there is no abnormal vibration, and there is no oil leakage at the shaft seal.
Post time: Feb-26-2026