How many sets of contacts does a motor starter require at minimum?

A motor starter requires at least one set of contacts for each power lead to effectively control the operation of the motor. This means that if the motor is a single-phase motor, you would need two contacts (one for each lead), while for a three-phase motor, three sets of contacts would be necessary to control each phase effectively. The primary function of these contacts is to engage or disengage the power supply to the motor, ensuring safe and efficient operation.

In some cases, additional contacts may be required for features such as overload protection or auxiliary functions, but the fundamental requirement is that each power lead must have a corresponding contact. Therefore, the number of contacts correlates directly with the number of power leads, making the first option the minimum requirement. The other options may suggest configurations that are either excessive or not applicable in all scenarios.