DOL start, for motor with heavy starting duty

Operation mode: By pressing Start push button bridge contactor Q2 is energized and maintains itself via Q2 normal open auxiliary contact. At the same time, voltage is applied to the time ON delay T1 timer. The main contactor Q1 is energized by Q2 normal open auxiliary contact and maintains itself via Q1 normal open contact. When the set time – which corresponds to the start-up time of the motor - has elapsed, the bridging contactor Q2 is disconnected by T1 and can only be energized again after the motor has been switched off by pressing push button Stop. The normal close contact of Q1 prevents Q2 and T1 closing whilst the motor is running. When overload occur, normally closed contact 95-96 of thermal overload relay  TF1 is opened and the motor stops.