Model of water-turbine generator set HL123-WJ-84 and TSW143/35-6, pilot bearing two units over the years with varying degrees of bearing in the generator high temperature, direct threat to the safe operation of units, power plant maintenance technician after repeated practice, and ultimately eliminate this fault.
1 symptoms for three wheel horizontal water-turbine generator set units, when units at full capacity after a continuous run, bearing temperature exceeds 60 ° c, temperature protection notice signal, backward two Vavin, water 48~50℃, 54~56℃ respectively. To avoid Bush burning, units are usually the highest take only 460 kW (90%) about load, three bearing temperature is within the specified values.
2 fault analysis
2.1 generating unit installation quality problems for turbine bearings sleeve bearings, bearing in operation temperature is too high, indicating friction between shaft and bearing, which could be due to quality issues, as mounted in the shaft joins centering, gap, spindle bearing contact point, Bush swing and other aspects of a process does not meet the technical requirements, can lead to temperature is too high. Power plant has been installed in each unit overhaul quality as important means for elimination of faults, record carefully before dismantling machine bearing technology parameters on the one hand, on the one hand, requested the mechanical overhaul of technicians presided over the installation, to ensure that the process of art meet the technical requirements for the installation of small hydro units, but the fault isn't gone, indicating failed for another reason.
2.2 quality problem of lubricating oil in the pilot bearing is oil-oil cooling ring with radial bearings, lubricating oil below the spindle of these bearings, oil separation, operating as generator oil cooling coil with spindle with lubricant poured on to the shaft neck, fell after bearing contact surfaces of oil tank, the oil kept flowing, lubricate bearing on the one hand, on the one hand take the heat on the Bush. If the oil is not qualified, bearing friction increases, temperature rise; oil cooling ring does not turn, you cannot take oil circulation lubrication and cooling. Maintenance technician 30# exclusively to the bearing to rejoin standard turbine oil, running from the eye to see two oil cooling ring rotate evenly, with oil and normal, but the symptoms failed to eliminate, exclude oil-type reasons.
2.3 generator winding cooling air duct issue HL123-QJ-84 hydroelectric generator in the front end cover with guide shaft seat to get near, 180 mm the distance between the two, running observed thermal wind blowing into the front housing of the generator windings, hot air bearings heat up, thus affecting the natural cooling of lubricating oil and cause bearing temperatures. Cooling with internal fan-cooled generator windings, during normal operation, along with the rotation of the rotor blades from both ends around the generator cooling air suction, cooling air across the surface of the rotor and the stator windings and iron core radial shroud, flowing from the motor side. Note, once close to the generator test at both ends, back air suction front blowing air out, indicates that the winding cooling air duct has a problem. Another reason is the Guide bearing temperature measurement using pressure-type fan-shaped thermometer, the conduction of thin hose is blowing hot air for a long time, causing measuring error, measured by mercury thermometers, hot air thermometer measured values inflated by about 4 degrees centigrade.
3 disassemble hang out of the rotor to check measurements, smooth flow of ventilation slot of stator core, but mounted on both ends 16 along the circumference of the rotor blades relative to the hinge centre line is not straight, relative deviation of 8 mm at both ends. Twist out and end all fan blades, hole in one direction fans widened 8 mm, back when the blade edge is relatively parallel to the hinge Centre at both ends so that operation of fans on both sides of the rotor into the air flow in the same direction on the contrary. Increased between the generator housing and shaft seat with a homemade circular windshield windshield with galvanized iron sheets and round steel bar welding, wind screen slightly larger diameter than the diameter of the generator, to block the hot air blowing directly in the pilot bearing. For generator cooling duct processing, unit operation with continuous full load, pilot bearing high temperature phenomena disappear, power is operating normally.
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