Reason for bearing temperature increase:

(1) The bearing cooling water is interrupted.

(2) Deterioration of oil quality, uncleanness of the oil itself, or deterioration of the oil during operation. If the moisture in the oil increases, it will cause an increase in the acidity of the oil, reduce the lubrication effect of the oil, cause corrosion of the bearing shells, and cause an increase in bearing temperature.

Phenomena:

(1) The fault light plate of the water turbine machinery next to the turbine lights up, indicating that the instrument temperature of the bearing increases, and the signal relay acts.

(2) There is an alarm bell ringing

(3) Send out a fault signal indicating an increase in bearing temperature.

(4) The black needle of the thermometer dial (expansion thermometer) coincides with or exceeds the yellow needle.

Processing

When the temperature of the bearing increases, the first step is to determine whether there is a malfunction. If it does increase, the following measures should be taken:

(1) Check if there is any abnormal noise in the bearings and check if there is any abnormality in the bearing swing.

(2) Check whether the cooling water pressure, water flow and Plumbing are normal. If the water pressure is low, it may be due to filter blockage and cannot be dealt with in a timely manner. When it is confirmed that it can work, it can be shut down and put into use.

(3) Take an oil sample to observe if there is any change in the color of the oil, and conduct laboratory tests to see if it has deteriorated. If deterioration is confirmed, the machine should be shut down and replaced with new oil. 

(4) The oil pressure of the governor should be checked. If the oil pressure is low, it may cause the cooling water hydraulic valve to close.

(5) Check whether the oil level of the oil pointer is normal. If not, check whether the oil drain valve of the oil tank is closed tightly. If it has been tightly closed, oil should be replenished. If the sealant pad leaks oil, the machine should be shut down for processing

Ultimate cooling of bearing grease strength

The strength limit of lubricating grease refers to the shear stress that causes the sample to start flowing, also known as the ultimate shear stress or strength limit stress, abbreviated as the strength limit. Letter for strength limit of lubricating grease τ Represented in Pa.

The standard method for determining the ultimate strength of lubricating grease is SH/T 0323-92, which measures the maximum pressure of lubricating grease when it is displaced in a plastic threaded pipe at the test temperature and replaces it with the strength limit value.

The strength limit of lubricating grease largely depends on the type of thickener and its amount in the grease. As the soap content increases, the strength limit also increases. The strength limit of lubricating grease is related to temperature. The higher the temperature, the smaller the strength limit of the grease; As the temperature decreases, the strength limit of the grease increases. The upper limit of the applicable temperature for lubricating grease can be roughly explained based on the strength limit at high temperatures. In practical use of lubricating grease, the applicable range of the strength limit of lubricating grease is approximately 100-300Pa. Generally speaking, the flowability of lubricating grease is often predicted based on its strength limit at high temperatures, while its ability to flow normally is predicted based on similar viscosity values at low temperatures.