What primarily distinguishes a start capacitor from a run capacitor?

The distinguishing feature of a start capacitor is that it provides a higher capacitance for short bursts of time, which is essential for initiating the motor's startup process. Start capacitors are designed to give the motor an initial boost of torque, allowing it to overcome inertia and begin moving. This higher capacitance enables a significant increase in current during the brief moment of startup, rather than maintaining a continuous flow.

Once the motor reaches a certain speed, the start capacitor is typically removed from the circuit, often through a relay or switch, allowing the motor to operate with a lower capacitance run capacitor. Run capacitors, on the other hand, are intended for continuous use, providing a smaller but consistent level of capacitance that helps maintain the motor's efficiency and performance during its operation.

Understanding the specific roles of these capacitors helps clarify why start capacitors are characterized by their ability to contribute high capacitance for short durations, while run capacitors are designed for lasting support during normal operation.