FIELD: electrical engineering. SUBSTANCE: operating mechanism is used for multipole circuit breaker incorporating change-over device coupled with tripping hook and switching rod as well as ratchet-and-pawl gear engageable with hook for loading or tripping operating mechanism with ratchet-and-pawl gear engaged or disengaged, respectively. Disengaging ratchet-and-pawl gear has disengageable operating facilities that function to automatically trip the pawl upon occurrence of short-circuit current exceeding calibrated threshold determined by flexible means; instruction for mentioned automatic tripping is ensured due to mechanical reaction set up by effect of electrodynamic correction that causes extremely fast turning of pawl for disengaging tripping ratchet-and-pawl gear before tripping component starts operating. EFFECT: increased electrodynamic force and breaking capacity, reduced tripping force and breaking time at short circuit and heavy current. 7 cl, 4 dwg
