Most of the domestic motor production enterprises take the cast iron machine seat as the first choice, but with the continuous extension of the national environmental protection policy, the box machine seat will extend down from the large size products, especially for the small batch products with special requirements, the box machine seat can just make up for the time cycle and cost of putting the mould into the cast iron machine seat. Compared with corrugated steel plate pedestal, box pedestal is widely used in large motors in China.

There are many specific types of box structure, and the shape, processing and assembly mode of its parts are different. The seat of box structure is usually welded with steel plate, and other main components are outer cover, base, stator, rotor and bearing. Because the outer cover does not bear the load, it only plays the role of protection and cooling system, and can be made of steel plate with thickness of about 2mm. The outer cover can be integral, or it can be made up of the upper and lower parts. The base should bear the gravity and all kinds of forces or torque of the whole motor, and requires higher strength and stiffness, which is usually made of thicker steel plate welding (can also be cast). The stator is completely separated from the base and outer cover The independent parts of the whole enter the base as a whole. The bearing of the shaft can be supported by hydraulic bearing or sliding bearing, which are installed in a separate bearing pedestal. In order to facilitate disassembly, the bearing seat is divided into upper and lower halves at the center line of the shaft.