What is not included in open-type starters?

The correct answer is that an enclosure is not included in open-type starters. Open-type starters are designed without a protective casing, allowing for easy access to the internal components such as the control circuit and starter elements. This design facilitates maintenance and troubleshooting, as technicians have direct access to the wiring and components.

In contrast, the other components serve essential functions in the operation of the starter. The overload is a critical safety feature that prevents damage to the motor by interrupting the circuit when excessive current is detected. The coil is responsible for energizing the circuit and engaging the starter, while the holding contact maintains the circuit once the starter is engaged. Thus, while overloads, coils, and holding contacts are vital components in an open-type starter, the lack of enclosures is a defining characteristic of this type.