The 3RU11 thermal overload relays up to 100A are designed for current-dependant protection of applications with normal start-up conditions against impermissably high rises in temperature as a result of overload or phase failure. An overload or phase failure causes the motor current to rise above the set rated motor current. Resetting takes places manually or automatically after a recovery time has elapsed. The 3RU11 thermal overload relays are electrically and mechanically optimised to the 3RT1 contactors such that, in addition to individual mounting, they can also be directly mounted onto the contactors to save space. The 3RU11 thermal overload relays are designed for the protection of three-phase and single-phase AC and DC motors. If single-Phase AC or DC loads are to be protected using the 3RU11 thermal overload relays, all three bimetal strips should be heated. The 3RU11 thermal overloads relay is available for normal start up conditions in Class 10.