What are the main loads on the machine base during the motor operation?

Update:05 Dec 2019
Summary:

The main load of the machine base during the operation […]

The main load of the machine base during the operation of the motor:

(1) Gravity load is generally the stator's own weight. In motors with end-cap bearings, the weight of the rotor must be supported, while in suspended hydro-generators, the weight of the rotating part of the unit and the upper frame must be supported.
 
(2) Radial force caused by unilateral magnetic tension and core thermal expansion.

(3) In the case of internal pressure installation and full-circle punching, some parts of the machine base must bear the axial rebound force of the iron core; for suspended hydro-generators, they must bear the axial water thrust.

(4) Torque. Including transient electromagnetic torque when the load suddenly changes and the generator is short-circuited.

Among the above loads, torque is the most important. In addition, during the processing, transportation, and installation of the general motor frame, it will also be affected by clamping force, cutting force, lifting force, etc. For motors that require sealing (such as hydrogen-cooled turbo-generators or explosion-proof motors), The machine base is also subject to the test pressure. When using end cap bearings and belts (or gears and other transmission mechanisms) for transmission, the machine frame and its feet will also be affected by the belt tension (or the force of the gears and other transmission mechanisms). . Therefore, when designing the machine base, the mechanical calculation of the general machine base often includes the calculation of its stiffness, strength and natural frequency. The strength calculation of the seam plate bolts is required for the half-frame, and the foot plate welds are required for the welding machine base. The calculation of stress is mainly the stiffness calculation of the machine base.