Which type of contacts does an auxiliary switch typically use?

Auxiliary switches typically use Form C contacts, which are designed to provide flexibility in circuit design. Form C contacts have both normally open (NO) and normally closed (NC) configurations within the same switch. This allows for more versatile control and integration into various applications, enabling the creation of complex control schemes without the need for multiple switches.

For instance, in motor control systems, an auxiliary switch with Form C contacts can simultaneously control the power to a motor (normally closed) and provide feedback to an indicator light or alarm (normally open). This dual functionality is crucial for applications that require simultaneous operations or safety interlocks.

Other types of contacts, like Form A or Form B, only have either normally open or normally closed configurations, which limits their application in scenarios requiring both functionalities. Form D contacts, on the other hand, are not commonly associated with auxiliary switches and typically represent more specialized configurations. Hence, Form C is the correct type for auxiliary switches due to its dual functionality capability.