DEVICE FOR ESTIMATING CONDITION OF STAMPING-TO- STAMPING INSULATION IN MOTOR STATOR STACK Russian patent published in 2003 - IPC

FIELD: electrical engineering; checking electrical motor stator stack for condition of insulation at industrial enterprises and repair agencies. SUBSTANCE: device has tool 1 for compressing steel stack stampings and to tightly hold measuring electrodes made in the form of needle contacts 2, 3 against them. Tool 1 has bearing rod 4 threaded over its entire length that terminates in head 5 on one end and square neck 6 on other; neck has threaded central bore to secure wing-nut 7 with aid of screw 8; strung onto the latter are hold-down strips 9 and 10, each being provided with needle contacts 2 or 3 with conductors 11 and 12 connected to them. Hold-down strips are stiff metal members. Hold-down strip 9 has non-threaded hole 13 and is fixed on bearing rod with aid of head 5, nut 14, and locknut 15 so that bearing rod 4 is free to turn within hole of this strip. Other hold-down strip 10 has two holes 16 and 17; hole 16 is threaded and serves to receive bearing rod 4 for its displacement; hole 17 is non-threaded and receives one end of locking rod 18 whose other end is welded to first hold-down strip 9. Each hold-down strip has additional hole for fixing needle contacts 2 and 3. Each needle contact terminates in threaded binding post 19 for securing hold-down strip in additional hole with aid of nut 20; insulating gaskets 21, 22, 23, 24 and sleeve 25 fitted onto needle- contact binding post 19 are placed between nut 20 and hold-down strip. Conductors 11 and 12 are connected to instrument 26 used for measuring insulation resistance of steel stack and needle contact. Spring-loaded needle contact 27 is attached through threaded joint to sleeve 28 fitted onto bearing rod 4. Sleeve has diameter greater than that of bearing rod and is free to move over the latter. Screw 29 provides for reliable locking of sleeve and its tight abutment against bearing rod. Tight fitting of spring-loaded needle contact to inner bore of stator core is afforded by spring 30 fitted onto threaded bolt of spring-loaded needle contact. Sleeve wall has two drilled holes of which one hole is of greater diameter meant to pass threaded bolt for fixing spring 30 and spring-loaded needle contact 27 in hole of smaller diameter. EFFECT: enlarged functional capabilities; enhanced precision of locating hot spots in stator stack. 1 cl, 2 dwg