In response to the special requirements of equipment applications, variable frequency power supplies, and frequency converters have become a product of the times. Regarding the three-phase AC motor, the inverter is ly used for power supply instead of the variable frequency power supply when the motor is used in variable frequency at the customer terminal. The rich harmonic components to the magnetization of the shaft, which induces the shaft voltage and generates the shaft current.
To prevent the axial current from flowing through the angular contact ball bearings, there are three options: one is to install a grounding carbon brush; the other is to use insulating angular contact ball bearings; the third is to use an insulating angular contact ball bearing sleeve structure. Today we only touch on one topic: electrical insulation angular contact ball bearings, that is, anti-electric corrosion angular contact ball bearings...insulating angular contact ball bearings include everything that can prevent current from passing through the channel "outer ring - rolling body - inner ring" includes Hybrid ceramic angular contact ball bearings and electrically insulating angular contact ball bearings.
Hybrid ceramic angular contact ball bearings: The inner and outer rings of the angular contact ball bearings are made of angular contact ball bearings steel, and the rolling elements made of silicon nitride are combined into insulating angular contact ball bearings. In addition to having good electrical insulating properties, it can operate at higher speeds. Electrically insulating angular contact ball bearings have a 100-micron thick alumina coating on the outer surface of the outer or inner ring, which can withstand DC voltages of less than 1000VDC, both inner and outer rings with ceramic Coated electrically insulating angular contact ball bearings or hybrid ceramic angular contact ball bearings with rolling elements made of silicon nitride can prevent the passage of electric current and have the insulating ability.
Insulating angular contact ball bearings can cut off the shaft current circuit; generally speaking, it is very difficult to eliminate the potential difference inside the angular contact ball bearings. But assuming we can stop or greatly reduce the current flow through the angular contact ball bearings, we can prevent electrical corrosion of the angular contact ball bearings. Various insulating angular contact ball bearings are currently designed for this purpose. The insulation method of angular contact ball bearings is selected according to the type of voltage generated.
