All of the following are types of starters for electrical motors except?

The correct choice identifies "Actuator" as not being a type of starter for electrical motors. An actuator is a device that converts energy into motion and is typically used in systems to perform actions like moving or controlling a mechanism or system, but it is not involved in starting an electrical motor.

In contrast, the other options refer to devices or methods that specifically serve to start electric motors. An autotransformer is a type of transformer that can adjust voltage levels, making it effective for starting motors by reducing the voltage supplied to the motor during startup. This helps in managing the inrush current and reducing mechanical stress.

Reduced voltage starters utilize various methods to decrease the voltage to the motor during startup, which aids in reducing starting current. This is important for large motors, as it helps prevent electrical and mechanical issues during startup.

Resistors can also be used as part of a starting method by providing resistance in the circuit to limit the initial current flowing to the motor, which helps to manage the starting torque and protect the motor.

These reasons clarify why "Actuator" does not fit into the category of motor starters, as its primary function differs from the techniques employed to initiate the operation of electrical motors.