The RW overload relays protect loads against overheating caused by overloads or phase loss. When we have an overload or a phase loss in the circuit, the motor current increases. Such current rise activates the tripping mechanism that will actuate on the auxiliary contacts 95-96 (NC) and 97-98 (NO). The auxiliary contacts disconnect the load by means of a contator. The time for disconnection is related to the overload current and the current set on the relay, which is properly represented on the relay tripping curve. After the trip, it is necessary to wait for the system to reestablish in order to do the reset, which can be done automatic or manually.

The RW overload relays were designed to protect three-phase and single-phase AC motors, and DC motors. If the RW overload relays are used in the protection of single-phase AC loads or DC loads, the wiring diagrams presented in this catalog must be respected.