How are 3-phase motors typically started?

Three-phase motors are typically started using direct-on-line (DOL) starters or soft starters due to the characteristics and demands of three-phase systems. DOL starters connect the motor directly to the power supply, providing full voltage from the start, which allows the motor to reach its rated speed quickly. This method is efficient and commonly used for smaller motors where the starting current impact on the power system is manageable.

Soft starters, on the other hand, control the voltage and current during the startup process, gradually increasing them to limit the inrush current and mechanical stress on the motor. This is particularly useful in applications where a sudden surge of electrical power could lead to damage or tripping of system components.

Other methods, such as using capacitors or applying a DC voltage, are not typical starting methods for three-phase motors. Capacitors are more relevant in single-phase motor applications for providing phase shift, while DC voltage isn't feasible for starting an AC motor directly. Direct connection to the grid is not specific enough to describe a typical starting method, as it could imply bypassing protective devices or starter configurations, which could lead to operational issues.

In summary, using DOL starters or soft starters ensures effective and reliable starting of three-phase motors, balancing quick performance with