Four sets of bearings were replaced consecutively at the shaft extension end of a motor, which was eventually found to be due to shaft voltage. Shaft voltage is a frequent problem in the operation and testing of high-voltage and low-voltage high-power motors.
In order to ensure the normal operation of large motor bearings, manufacturing and repair units often check the motor’s shaft voltage; when the operation of the motor bearings are often found to be malfunctioning, determine the problem of the shaft voltage, but also to check the measurement. Shaft voltage is the voltage generated between the two shaft ends of the motor or between the shaft and the bearing.
Empirical values for axial tile motor shaft voltage control
For axial tile motors, the impact of shaft voltage on the performance of the motor is relatively large. The oil film of the lubricant has a certain insulating effect, a small shaft voltage produces a small shaft current has little effect on the axial tile, when the effective value of the shaft voltage is less than 0.5V, it will not cause any failure to the sliding bearing. When the shaft voltage is large to a certain extent, the shaft voltage will oil film breakdown, constitute the circuit of the shaft current, there is a certain harm to the axial tile, when the shaft voltage is greater than 1.5V, the axial tile will be burned, in the surface of the tile alloy burned out many pits and scars.
Empirical values for rolling bearing shaft current control
Axial current is more sensitive to rolling bearings, axial current greater than 1A greatly reduces the life of the bearing; greater than 2A, the bearing is burned when used for a few hours. Therefore, the repair unit stipulates that the shaft current for rolling bearings should not be greater than 1A, less than 1A is called harmless shaft current.
Damage to shaft extension by shaft voltage and solutions
In addition to the damage to the bearings, in the motor type test or operation, will cause different degrees of abrasion on the motor shaft extension; some testers use in the shaft extension on the oil solution, but for the shaft voltage is relatively large situation does not work, there are also manufacturers use soft carbon brush pressure relief, including some bearing manufacturers also through the supporting pressure relief soft carbon brush protection bearings, but has not yet been a good promotion.
Large motor shaft voltage and shaft current control is the problem faced by each production enterprise, the promotion and use of insulated bearings effectively solve the problem, but the cost of bearings to be high; the same specifications of the product is not every motor has a shaft voltage, and the production process also has a greater relationship between how to design, process control and manufacturing process can be predicted on the motor shaft voltage, is the direction of the motor production enterprise research.
Post time: Jul-02-2024
