9065CT9701R03/21

Thermal Overload Relay Trip Characteristics

Melting alloy and bimetallic overload relays are designed to approximate the heat actually generated in the motor. As the motor temperature increases, so does the temperature of the thermal unit. The motor and relay heating curves (in the figure Overload Relay Trip Curve) show this relationship. When properly applied, no matter how high the current drawn, the overload relay provides protection without tripping unnecessarily.

See the figure Overload Relay Trip Curve for the motor heating curve and overload relay trip curve. The curves show the overload relay tripping before motor damage occurs.

Overload Relay Trip Curve

QR Code is a registered trademark of DENSO WAVE INCORPORATED in Japan and other countries.

Was this helpful?