Which type of starting method applies full voltage to the motor at all times?

The part-winding starters method applies full voltage to the motor at all times by connecting only part of the winding initially during startup. This allows for a reduced starting current while maintaining the full voltage to the motor, which eventually allows the full winding to be utilized once the motor reaches a certain speed. This method is often used in applications where the motor is larger and experiences high starting torque requirements.

The soft-start method uses electronic controls to gradually ramp up the voltage and current to the motor, thus not applying full voltage immediately. Wye-delta starting initially connects the motor windings in a wye configuration to reduce the voltage and current, then switches to delta for normal operation, which again does not apply full voltage at all times initially. Primary resistor starting involves placing resistors in the circuit to limit voltage and current at startup, therefore not supplying full voltage at all times.