What is the major difference between a relay, a contactor, and a starter?

The major difference between a relay, a contactor, and a starter lies in the size of the load they can handle. Relays are typically used for low-power applications and control signals, whereas contactors are designed for higher power loads, managing the switching of large electrical loads like motors and lighting. Motor starters, while incorporating contactor functionality, also include additional components like overload relays for motor protection, which makes them suitable for starting and stopping motors safely and efficiently.

This distinction in load capacity is essential, as it determines where each device can be appropriately used in HVAC systems and other electrical applications. Understanding this difference helps ensure the right component is selected for a specific application, promoting safety and effectiveness in electrical installations.