7 30 Oper ating Instr u ctions CM Synchronous Ser v omotors Malfunctions 73 B rake faults Fault Possible cause Remedy Brake does not release Incorrect volt age on brake control unit A pply correct volt age Brake control unit failed Replace brake co ntrol system check internal resist ance and insulation of brake coil check switchgear Max permitted worki ng air gap exceeded because brake lining worn down Consult with SEW EURODRIVE customer service V o lt age drop on connecting harness 10 C orrect connection volt age check cable cross section Brake coil has interturn fault or short circuit to exposed conductive p a rt Consult with SEW EURODRIVE customer service Motor does not brake B rake lining worn down Consult with SEW EURODRIVE customer service Incorrect braking torque Consult with SEW EURODRIVE customer service Manual brake release device not set correctly Set the setting nut s correctly Brake is applied with time lag Brake is switched on AC volt age side Switch on DC and AC volt age sides observe wiring diagram Noise in the brake area Pulsating torques due to incorrectly set fre quency inverter Checkcorrect setting of freq uency inverter according to operating instructions