The squirrel cage in the synchronous motor rotor is specifically sized to operate at startup and with Gates B154 probable machine load oscillations during stepping operation. Unlike the cage of the induction motors, which by the very principle of operation, is sized for both the starting condition and the operating condition, having to properly meet both situations. Because of this specificity of the squirrel cage of synchronous motors, the starting condition of this type of electric machine can be adjusted during the design of the machine according to the particularities of the load to be driven by the engine, the starting method used and the conditions operation.
This is why it is important to know this information from the design stage of the machine, because in this way the machine can be applied exactly to the operating condition for which it will be designed. For this reason, in cases where an existing synchronous motor is used to trigger a load different from the original load, it is important to analyze the starting and the characteristics of the machine to make sure that the synchronous motor can start the new load correctly.