Thermal Overload Relays Tripping Class 20 ABB NewMotor Protection general Tripping classes of the thermal overload relays It is very important to choose an adequate protective device for Standard tripping classes are 10 A, 10, 20, 30. The tripping the safety of the motor during operation and for its durability. class indicates according to IEC 60947-4-1 the maximum The efciency of protection methods varies according to the ap- tripping time in seconds under specied conditions of test at plication. The overview below will help you to choose. 7.2 times the setting current and specics tripping and non trip- There is no general rule and we are available to advise you for ping times for 1.5 and 7.2 times the setting current. special applications and especially in the case of difcult start- ing. An economic and effective protection are thermal overload Construction and function relays with protection against: General > Overload Thermal O/L relays and their accessories meet UL, Nema, CSA > Phase failure imbalance and most other important international standards (IEC), European > Phase loss standards (EN) and the most important national standards. They meet the certication and approval directives required through- Description out the world. Available for starter construction with A Line contactors and Thermal overload relays are 3 pole. The motor current ows separate panel mounting through their bimetals (1 per phase) which are indirectly heated. Designed for close couple mounting separate base Under the effect of the heating, the bimetals bend, cause the mounting available for all overload relays relay to trip and the position of the auxiliary contacts to change. Full automatic function, Manual reset, Test phase or Reset The relay setting range is graduated in amps. In compliance with can also be adjusted to function as a stop button international and national standards, the setting current is the Remote trip and reset option available motor nominal current and not the tripping current (no tripping Screwdriver guide holes, all terminal screws are available at 1.05 x setting current, tripping at 1.2 x setting current). The from the front tripping curves (cold or warm starting, 3 phases and 2 phases) Trip indication are shown in the main catalog. Ambient compensation -25 C to +55 C The relays are built to be self protecting in the event of an over- (-13 F to +131 F) load until the short circuit protection device is activated. Function of the thermal overload relays Press Contacts Relay tripped Relay not tripped blue button Manual Automatic Manual Automatic Terminals L1, L3, L5 NC 95-96 open open closed closed Manual test NO 97-98 closed closed open open Button R Reset Manual or NC 95-96 closes when automatic reset Buttons Frame size pressed Trip indication light TA ... DU NO 97-98 opens when Buttons Reset button Amp setting pressed range Button R/O Reset Tripping contact (95,96) NC 95-96 closes when opens when opens when Buttons Buttons Buttons released pressed pressed Signaling Terminals closes when closes when contact (97, 98) T1, T2, T3 Buttons Buttons released released NO 97-98 opens when Buttons pressed