INDUCTION MOTOR Russian patent published in 2001 - IPC

FIELD: motors for fast-braking systems such as lifts. SUBSTANCE: motor has wound stator press-fitted into frame, rotor mounted on steel shaft, frame-coupled front and rear endshields provided with through bores, and shaft-mounted fan with shroud. Motor is provided with braking device installed between rear endshield and fan; braking device has annular electromagnet with core and coils screwed to seat on rear endshield and annular armature spring-loaded relative to annular electromagnet and mounted for contacting this electromagnet in working condition at the same time applying voltage across motor winding and electromagnet coil and breaking this contact in de-energized condition at the same time coming in contact with fan. Fan mass amounts to at least 5% of motor mass; fan is spring-loaded relative to endshield, has thrust washer on shaft end, and is mounted on shaft through key for axial displacement and for setting up clearance of (0.2-2.05) mm between annular armature and annular electromagnet core. Stud is driven in shaft end and nut is turned onto this stud to engage thrust washer of fan. EFFECT: enhanced reliability and mechanical endurance under emergency braking and multiple on/off operating conditions. 12 cl, 19 dwg