REPAIR OF HIGH VOLTAGE ELECTRIC MOTORS
The main nomenclature of high-voltage electric motors, that are being repaired, 6-10 KV:
– asynchronous with a short-circuited rotor of the AN-2 series, AZO, GIVEN, SO, 4A, A4, DAZO, 4AOV, NAME, AV, VA with a phase rotor of the AKN series, AOK2, AOK4.
– explosion-proof with a short-circuited rotor of the VAO series, AZMV, WOW, "Ukraine"; with a phase rotor of the "Ukraine" series.
– Synchronous SD, SDS, SDN, CD2, SDM, SDV, SDR, SDKP, STDM, SDMZ.
Breakdowns of high-voltage electric motors, which are most common:
– short-circuiting of a high-voltage electric motor is the cause of the breakdown of the movement of the turns of the sections or overheating (elevated temperature);
– interphase breakdown of a high-voltage electric motor – the cause of this type of malfunction is the movement of the front parts of the sections, circuit movement.
– breakdown of the stator winding (phase rotor) on the housing - the cause of this breakdown of the high-voltage electric motor is the movement of the winding, vibrations, loosening of bandages;
– mechanical breakdowns of high-voltage electric motors are as follows, as, failure of rolling bearings, sliding bearings, body damage, fan damage, failure of insulators, rotor imbalance.
After the correct diagnosis, the repair of the high-voltage electric motor begins. Depending on the type of malfunction, the repair includes the following operations:
• dismantling of the stator winding;
• removal of casing and winding insulation;
• stator repair (tests of the "iron" of the stator for heating and specific losses);
• restoration of the landing surface for the installation of the stator iron package (pressing out, surfacing, threading under the package, pressing);
• manufacture and replacement of the stator winding;
• elimination of mechanical breakdowns of conductors;
• insulation of winding and body insulation;
• High-voltage tests of stator sections;
• stacking of sections , drawing up a scheme;
• hull repair, fan;
• restoration of the working surfaces of the rotor according to the specified dimensions (surfacing, boring, grinding);
• replacement of the rotor shaft (if necessary);
• rotor balancing;
• repair or replacement of bearing assemblies;
• replacement of rolling and sliding bearings, insulators;
• acceptance tests: measurement of insulation resistance of the stator winding relative to the body/absorption coefficient, testing the insulation of the stator winding for electrical strength with increased voltage of industrial frequency, resistance of the stator windings at direct current, checking for the absence of inter-turn short circuits, idle speed check, level of vibration and control of the thermal state of the responsible electrical/machine components.
When repairing high-voltage electric motors, the most modern high-quality insulating materials are used, bearings imported by SKF firms, FAG, etc.
Insulating materials: sintaflex, elmikatherm, tapes of mica LSK, LSU, LSEP; mylar tapes, tapes are high temperature ,lavsan cord, fiberglass
STEP-1.
2. Mechanical components - bearings of domestic and imported production by SKF firms, FAG etc.
3. High-quality, appropriate lubricants are used to lubricate the bearings.
All materials and assemblies, used in repair and maintenance, have relevant quality certificates.