Once the editor of Dalan Motor and his friends handled a batch of three-phase asynchronous motors disassembled due to a fault. Disassembly and inspection revealed that some bearings were scattered, some bored, or the windings were even burned due to overload. However, the common feature of all faulty motors is dry bearings or black grease.
Further understanding revealed that the customer did not use the specified grade of grease when maintaining the motor. This information further confirmed the service personnel's judgment that there was a problem with the grease used.
Different motor manufacturers will choose the appropriate grease according to the characteristics of their products and the corresponding operating conditions. Some manufacturers will determine the specific grease according to the pole number of the motor, and some manufacturers will determine the appropriate grease according to the special operating conditions. When choosing grease, people will pay attention to the drop point temperature of the grease, but the drop point temperature does not mean that the working temperature can meet the requirements.
The working temperature of the lubricating part is an important basis for selecting grease. The typical component that uses grease is a rolling bearing. As far as the relationship between bearing temperature and grease life is concerned, for every 10-15 ° C increase in bearing temperature, the life of grease decreases by about 1/2. Considering the temperature resistance of grease, not only depends on the drop point of grease, but also considers the type of base oil, anti-oxidation performance, evaporation performance and so on.
The editor participated in a batch test of the drop point of grease, and at the same time conducted a comparative test on greases of different models and brands. The better quality grease can drop at the marked drop point temperature, and the color of the grease is not. Obvious change; one of the samples is a grease that has a problem on the market. The drop point temperature on the packaging is 380 degrees. When the temperature is actually increased to 200 degrees, the grease appears blackened. Although there is no drop point, it has been seriously deteriorated.
In order to verify the suitability of the grease, qualitative verification can be carried out through a full-performance type test, especially for ordered products with special working conditions, it can be verified by simulating the working environment; some motor manufacturers verify the lubrication during the inspection test The grease method is not desirable because the motor's short-time no-load operation cannot be consistent with the actual on-load operation.
Facts have proved that for products with a relatively high ambient temperature in operating conditions, the temperature rise of the motor and the actual operating temperature of the motor and the corresponding bearing temperature should be considered at the same time, and the heat bearing capacity of the bearing itself and the satisfaction of the grease should be considered.
ï¼ï¼ï¼ï¼- Editor in charge: Dalan Oil Pump Motor 02-Procurement Consultant
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