When selecting a synchronous motor, you must prioritize rated power (kW/HP), rated torque, and synchronous speed (RPM) to ensure it meets your mechanical load requirements. Pay close attention to the excitation method (permanent magnet vs. wound rotor) as this impacts efficiency and maintenance. Additionally, verify the insulation class (Class F or H is standard for industrial use) and the IP Rating (e.g., IP55 for dust/water resistance) to ensure the motor can withstand your specific operating environment.