The high-voltage motor bearing system is a crucial component. Common faults in high-voltage motor bearing systems include excessive noise and even fatal failures due to improper insulation. Ms. Can will discuss high-voltage motor bearing assemblies with everyone today.
High voltage motor rolling bearing structure
To improve the load-bearing capacity and service life of the bearings at the shaft extension end, rolling bearing assemblies generally adopt a three-bearing structure. That is, at the shaft extension end, a set of cylindrical bearings and a set of ball bearings are arranged in parallel. The cylindrical bearings bear radial loads, while the ball bearings only bear axial loads (therefore, a certain gap is usually left between the outer ring of the ball bearing and the inner circle of the bearing sleeve radially); while at the non-shaft extension end, a set of cylindrical bearings is used.
Of course, a two-bearing structure can also be used. Different motor manufacturers have different designs. From a theoretical perspective, a two-bearing structure is easier to position according to the principle of two points in a straight line, while a three-bearing structure has theoretically had positioning problems.
To prevent the bearing rings from running out of the motor, appropriate fit tolerances must be selected between the outer bearing ring and the bearing housing, and between the inner bearing ring and the shaft. The outer bearing ring at the positioning end is pressed shut by the inner and outer bearing cap stops, and the bearing cap is fastened to the bearing sleeve or end cover.
Both the bearing assembly at the shaft extension end and the bearing assembly at the non-shaft extension end adopt a labyrinth structure and are sealed with a sealing ring. This not only prevents the lubricating grease in the bearing chamber from leaking into the motor and damaging the coil insulation, but also prevents external dust and water from entering the bearing chamber, keeping the bearing clean.
High-voltage motors should be equipped with oil injection pipes and oil drain pipes to facilitate grease replacement and to allow for oil injection and drainage without stopping the machine.
The bearing assembly has an IP54 protection rating. IP55 may be required in some cases, such as for outdoor motors or motors intended for use in the open air.
High voltage motor sliding bearing structure
A sliding bearing is an independent component of a motor, fixed to the end plate of the motor base. Both sides of the sliding bearing are provided with an oil inlet, an oil level observation hole or an oil outlet, a bearing temperature sensing element mounting hole, an oil drain hole, and a heater hole. The oil inlet and oil outlet are for circulating lubrication with pressurized oil.
The sliding bearing is an end-cap type self-aligning spherical sliding bearing, with the bearing shell, bearing housing, and bearing cap in spherical contact. The sliding bearing adopts a floating labyrinth seal and air seal structure, which helps to prevent bearing oil leakage. An insulating layer is added to the bearing housing at the non-shaft extension end of the sliding bearing to prevent motor shaft current.
There are three lubrication methods for sliding bearings: (1) self-lubrication, which uses an oil ring to supply oil to the bearing; (2) pressure oil circulation lubrication, which uses an external oil pump, oil pipe and bearing to supply oil to the bearing; (3) composite lubrication, which is a combination of the first two lubrication methods, namely the combination of pressure and oil ring oil supply.
The basic housing protection level of the sliding bearing is IP44. If necessary, IP54, IP55, and IP54 and IP55 protection levels can also be used. On the basis of the IP44 protection structure, an additional waterproof and dustproof outer cover is added.
The bearing shell adopts a single clearance cylindrical structure, and there are two structural forms: thrust bearing shell and non-thrust bearing shell. The bearing shell with thrust bearing shell is only used to limit the axial thrust generated by the motor itself and does not bear external thrust load. If the motor using sliding bearing needs to bear external axial thrust, the customer must specify this when ordering.
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