In management practice, many small hydropower stations in rural areas or in individual countries lack the educational level of operators and lack of formal and systematic technical training. They lack the experience in operation and maintenance of generators for small hydropower stations, resulting in long-term low incidence of generators Effective operation has affected the safety and efficiency of hydropower stations.
1 Keep the generator clean
Regularly clean the generator surface of the oil and dust, periodically remove the generator brush powder, dust and brush powder is inhaled into the generator, will result in reduced generator insulation, and even cause a short circuit within the generator. Cleaning methods can be used to pump high-pressure air blow blowing, brush can also be used to clean, and then a clean cloth dipped in alcohol to remove dirt and brush powder, especially the generator brush slip ring parts should be regularly and carefully cleaned.
2 Always check and maintain the brush slip ring
The safe and stable operation of the generator, and the correct slip ring maintenance, the correct choice of brush, has an extremely important relationship. Often due to improper selection of brush, slip ring maintenance is not timely, accelerating the generator brush, slip ring wear. Occasionally worn toner and copper end, inhaling the coil end and cause a short circuit, burn the winding, resulting in the generator can not be normal operation, lack of reactive power output, affecting the safety and efficiency of the unit, therefore, often must brush the slip ring Check and maintain.
The running brush must be on the center line of the slip ring. The brush and the brush holder should not be too tight. Make sure the brush has a gap of 0.1 ~ 0.2 mm between the brush holders. size. Allowing the brush to have a small amount of longitudinal runout within the brush holder allows a small amount of sparking on the brush, but excessive beating or sparking may require maintenance. If the brush position is not on the centerline, adjust the brush bar or brush holder position, and the bolts that hold the brush braid should be tightened. Brush the spring must have a certain pressure, and can not be too tight, loose or loose uneven, the pressure should be adjusted to make the spring moderate and uniform size. Excessive brush wear, or use the wrong brush type, will have a serious spark burnout slip ring, it should be promptly replaced. Replace the brush to use the original model of the manufacturer of the original brush or slip ring technology requirements of the brush. If you do not know the type of brush, for the generator speed 1000 r / min and below, you can use D104 type graphite brush. The number of brushes should not exceed 1/3 of the total number of brushes each time, and the contact surface with the slip ring should be ground into a curved shape so as to be in good contact with the slip ring.
The surface of the generator slip ring should be round and smooth, otherwise it will accelerate the wear of the brush, causing the spark of the brush to be serious and ablating the slip ring. Slip ring surface singeing or a small groove, must be repaired. The method is to slowly turn the rotor, with a flat file forced flat pressure on the slip ring, the slip ring surface grinding, and then spread in the flat wood surface 00 fine glass sandpaper, slip ring surface polishing, and finally Use a brush to carefully remove filing and sandpaper. Large groove or brush slip serious circle, you must remove the slip ring with a lathe repair.
Poor contact between the slip ring and the brush generates high temperature, which can cause aging or even burnout of the insulating sleeve of the bolt on the slip ring and cause the excitation system to short-circuit. If the bushing is burned out and there is no replacement, replace it with a dry small bamboo tube. The method is to choose a dry bamboo (hollow bamboo tube should be the same diameter as the bolt), the bolt into the hollow bamboo tube, and slowly scraping the outer cylindrical bamboo so that the bamboo can be worn just wear the bolt Slip on the hole on the slip ring, cut off excess parts, install insulation pads, and fasten the bolts.
3 to strengthen the operation of the generator monitoring and inspection
3.1 generator winding temperature, generator bearing temperature inspection monitoring
For running generators, touch the generator housing with the back of the hand to check for abnormalities such as a normal temperature and a large change from the past.
Observing the generator outlet connector with the eyes to see if the temperature is too high, poor contact caused by fever joints. Not serious heat color is gray-black, severe red fever. You can also use the insulating rod, stick a little bit of water touched the generator phase of the test was the first pile, if the temperature is too high will emit heat. However, it should be noted that it is strictly forbidden to touch the two-phase wiring pile head at the same time to prevent short circuit. Can also shut down the power cut off, immediately touch the generator outlet connector and the excitation line connector to see if the temperature is too high, such as too high must be immediately processed.
Copper and aluminum wire connected, the connector should be copper or aluminum wiring nose or copper and aluminum equipment clamp, the best in the joint surface coated with a layer of conductive paste. Generator outlet connector must be tight and reliable, the upper and lower wiring bolts must have a gasket on both sides. Tighten the copper bolts must be tightened slowly, all tightened, but also check it again to ensure foolproof.
3.2 generator operation sound and vibration inspection monitoring
Generator anchor bolts loose or damaged, will cause the unit vibration, it should be tightened bolts or replace damaged bolts. Generator bearing parts abnormal vibration and noise, there may be lack of bearing oil bearing or bearing damage, must be refueling or replacement. The generator is a rolling bearing, the general choice of No. 2 or No. 3 sodium-based grease or calcium sodium-based grease, grease of different specifications can not be mixed to avoid grease deterioration. Each run 2 500 ~ 3 000 h, should be cleaned bearings, replace the new grease, grease should pay attention to the bearing cavity volume of 2/3 is appropriate. The normal generator should have a uniform "buzzing" sound during operation or it should be shut down immediately for inspection and overhaul.
3.3 generator current, excitation current, voltage monitoring
To the stator current, excitation current, voltage and power monitoring to prevent generator overload, phase loss, the generator stator, excitation system and generator external circuit failure and damage to the generator. Also monitor the operation of the generator has abnormal odor, abnormal odor generator, you must immediately stop checking and overhaul.
3.4 to prevent rodent damage
In practice, many generators found in mice room, bite the generator coil, a great harm to the generator. Therefore, to rodent in the generator room, but also to the generator inlet, cover the gap at the installation of protective net, and the generator cover and air slot on a regular basis to clean up.