A failure in which component might cause the motor to not start at all?

The motor starter coil is a critical component in the process of starting an electric motor. It is responsible for energizing the motor starter, which then allows current to flow to the motor and initiate its operation. If the motor starter coil is malfunctioning or not functioning at all, the coil will fail to energize the starter contacts. As a result, the motor will not receive electrical power, preventing it from starting.

In contrast, while other components might also cause issues related to motor function, they do not preclude the motor from starting outright if the starter coil is operational. For instance, a failure in relay activation could prevent proper engagement in some scenarios, but it may not completely stop the motor from starting if alternate pathways or systems are in place. An issue with the power supply line would cause the motor not to start, but this pertains to external factors unrelated to the motor's internal components. Similarly, if the overload trip mechanism is activated, it generally indicates that the motor is being prevented from running due to excessive load or fault conditions, rather than an outright failure to start. Thus, the motor starter coil's role is essential and directly linked to the ability of the motor to start at all.