Thermal overload relays are economic electromechanical protection devices for the main circuit. They offer reliable protection for motors in the event of overload or phase failure. Starter combinations are setup together with block contactors and mini contactors.
The thermal overload relays are three pole relays with bimetal tripping elements. The motor current flows through the bimetal tripping elements and heats them directly and indirectly. In case of an overload (over current), the bimetal elements bent as a result of the heating. This leads to a release of the relay and a change of the contacts switching position (95-96 / 97-98).
Characteristics of thermal overload relays range
- Trip class 10A or 10
- Special version with trip class 20 or 30*
- Manual or automatic reset selectable
- Trip-free mechanism
- Phase loss sensitivity acc. to IEC/EN6094-4-1
- 2 electrically isolated auxiliary contacts – 1 NO + 1 NC
- Test and STOP function
- Trip indication on the front
- Temperature compensation
- Ambient air temperature - operation: -25°C … +55°C
- Useable for AC- or DC-application*
- Suitable for three- and single-phase applications
- All phase are equipped with bimetal tripping elements
- All terminal screws are accessible from the front
- Special versions, suitable for protection of EEX e motors*
Available accessories
- Separate mounting kits*
- Busbar kits *
- Terminal shrouds*
- Remote trip and remote reset *
* selected devices only