Common faults and maintenance of transformer
Transformer burnout is a serious problem, caused by improper configuration, aging, including natural disasters, man-made damage. Some of the specific reasons:
( 1) distribution transformer high, low voltage sides without fuse. Although some have been loaded onto the drop type fuse and the clevis insurance, but the fuse element is made of aluminum or copper instead, resulting in low voltage short circuit or overload, the fuse can not be normal fuse burned down transformer.
( 2) the transformer high voltage line, mostly by overhead line lightning arrester in operation is introduced, due to not timely or not installed 10kV arrester. When burned transformer caused by lightning strike.
( 3) if it is used in rural transformer, because rural lighting line more, most of it is single phase power supply, coupled with the construction of the jumper optional sex and management is not in place, resulting in a partial phase operation with variable load. The long-term use, resulting in a phase coil of transformer insulation aging and burning.
( 4) some man-made damage: such as transformer lead wire is a copper screw, and overhead lines in general use aluminum core rubber line, due to improper operation, very easy to produce electrochemical corrosion between copper and aluminum. Transformer bushing flashover discharge are common anomalies.
Then a brief introduction of transformer of three common troubleshooting methods:
An internal circuit breaker, rapid maintenance method
Boot no voltage output, the whole no reaction. Available a multimeter to measure transformer coil outlet resistance or voltage can be judged. When measuring resistance to disconnect the parallel both ends of the coil component. Measure voltage, if the secondary coil are no voltage, but the primary coil ends with voltage, indicating primary coil circuit breaker. If the secondary only one coil voltage, the coils have circuit breaker. Circuit breaker fault for welding wire caused by mildew, occurs in the root of an outgoing line or winding process of varnished wire head welding point. Should be carefully checked each terminal and pin welding point is broken. If no circuit breaker, the fault exists in the coil inside," one law" in search of available disconnected parts. The multimeter low barrier, a table document connected winding a wire, the other a pen tied a seam sewing the clothes, with each layer of coil spines on the edge of one turn, when the Spurs to a layer of sheet after rough without deflection, i.e. the layer coil has been circuit breaker.
For transformer disconnection fault occurred in the winding leading-out end of the root, should be first heated to softening of transformer, insulating paint magnet needle carefully pick coil, with similar diameter enameled wire or stranded cord and pick out the thread welded, then put on line welding in welding piece. If the frame on both sides of a baffle, the baffle shall be bent and broken, careful not to damage the coil and the lead wire.
When short circuit fault occurs in the winding of the innermost layer, remove the core, carefully pry out the skeleton, broken head, welding after extraction. With a thick cable paper stuck in the skeleton breakage, coated with insulating paint, the end inserted into the core.
Two, poor insulation quick repair method
Transformer insulation failure is energized line package partial arc discharge, human contact with hemp core electrical sense, test pencil test, neon light. Available multimeter high resistance ohmmeter test of transformer insulation condition, coil and the coil, coil and the iron core, insulation resistance should be greater than 10M ohm, if the measured resistance is much smaller than the 10M ohm, the poor insulation. For insulation fault, then the corresponding maintenance method can be carried out!
Three, the rapid maintenance method of internal short circuit
Transformer inner short circuit includes the coil inner coil and coil and core short-circuiting between. The occurrence of such failure, will appear transformer fever phenomenon, at the same time, the secondary coils of the transformer output voltage will also appear arrhythmias, and accompanied by burning AC 0.5A insurance tube and other phenomena, and is usually used to measure secondary voltage can be used to identify the short-circuit part. Detection, firstly the multimeter is used to measure the secondary winding of the voltage, if the voltage is higher than normal value, then is the primary winding short circuit exists; if a secondary winding of the voltage of the constant value was significantly reduced, the winding short circuit; if the secondary winding no-load voltage is basic and normal, then the electrostatic shielding layer is short circuit. Can also use multimeter electrical barrier to measure the DC resistance of winding method to judge roughly a short circuit to the site, a short circuit fault winding resistance values than normal value should be low, but slightly short circuit is not easy to judge. In actual application, a secondary winding of a transformer low voltage wires, coarse, short circuit condition is rare, generally occurring in the primary coil fault.
Repair of the internal short circuit fault method is: remove the transformer, and transformer core and coil, magnetic shielding, shielding copper ring short circuit and fasteners. Some of the transformer silicon steel sheet is inserted tightly, but have been varnished insulating treatment. Remove the silicon steel sheet, the first transformer placed beside the fire heated to 75 DEG C to 85 degrees C ( hand feel very hot, insulating paint slightly smoke ), so the silicon steel sheet of insulating paint softening, or the transformer into gasoline for L ~ 2 hours, so that the insulating paint softening. Then use the screwdriver will silicon steel sheet bar with a knife Tiqu, type E film adhesion is detached. Then a steel saw blade, grinding in grinding wheel thickness and width and silicon steel sheet intermediate blade thickness and width of substantially the same iron bar, pay attention to smooth straight face. The iron bar is inserted into the tick to horizontal cracks, aligning silicon steel sheet intermediate tongue, with a hammer to beat the iron bar, the E type silicon steel sheet roof, and the adhesion of the silicon steel sheet by a screwdriver pry, can be completely removed for silicon steel sheet.
The above information by the country electric switch factory for you, www.guofadq.com