More types of transformer failure, but the common fault phenomenon is nothing more than short-circuit, open circuit and leakage, and several other. The causes of these failures can be summarized into three aspects: First, the design is wrong; Second, poor production quality; Third, the use of conditions beyond the design requirements.
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Steps / methods
Transformer is still there is design, installation defects;
Check the transformer load current, operating voltage is normal;
Check the transformer leakage oil phenomenon, the oil level, oil color, the temperature exceeds the allowable value, oil immersed from the upper transformer oil temperature is generally below 85 ℃, strong oil air-cooled and strong oil-water-cooled transformers should be below 75 ℃ ;
Check the transformer high and low pressure porcelain casing is clean, with or without cracks, damage and flashover discharge traces;
Check the transformer terminals with or without bad contact, overheating;
Check the operation of the transformer sound is normal; normal operation with a uniform buzzing electromagnetic noise, such as internal discharge noise may be the breakdown of the winding insulation phenomenon, such as the emergence of uneven electromagnetic noise may be the core wear The core bolt or nut is loose.
Check whether the moisture absorber of the transformer has reached the saturation state;
Check the transformer oil cut-off is normal, leading to the gas relay cut-off and radiator cut-off is open;
Check the transformer explosion-proof pipe diaphragm is complete, diaphragm glass is engraved with a "ten" word;
Check whether the transformer cooling device is operating normally, heat pipe temperature is uniform, with or without tubing clogging;
Check the housing of transformer grounding is good;
Check the gas relay is full of oil, no gas exists;
On the outdoor transformer, focus on checking the foundation is good, with or without foundation sink, on the change Taiwan, check whether the pole is solid, wood, root rotten phenomenon.
On the indoor transformer, focus on checking the doors and windows are intact, check the blinds wire yarn is complete;
Other items that should be checked
When the transformer winding short circuit, the phenomenon is that the transformer temperature is too high, there is coke smell, smoke, the output voltage decreases, the output voltage is unstable. If you find these phenomena, you should immediately cut off the power, check. Short circuit due to the main reasons: the transformer damp internal mold, over time will make the insulation damage, resulting in serious leakage or short circuit; or due to the aging of the transformer insulation aging, insulation performance decreases, causing insulation breakdown, resulting in short circuit. In addition the sudden increase in supply voltage can also cause insulation breakdown, winding short circuit.
Transformer no output voltage when the circuit is open, the primary side of the input current is small or no input current. The main reasons for the resulting open circuit are: external lead wire breakage; lead wire and solder joint desoldering; line breakage by the collision and damp occurred after the internal mildew and so on. The company is located in:
Find the cause of the transformer failure, you can repair. For external faults, if the wire breakage, desoldering, you can re-welding and deep replacement of the new line; if the lead wire terminals and the core between the ignition or spark ignition caused by insulation between the terminals should be properly opened and Iron core, or the distance between terminals and terminals; if the insulating layer burns, it should be replaced or removed its charred part and sealed with epoxy glue.
For transformers that have a short circuit due to damp or have a high no-load loss, if the coil has short-circuited, the short-circuited wire must be removed and rewound. Generally due to damp and not caused a short circuit transformer, remember not to power, so as not to cause insulation breakdown, can be placed in the oven drying, restore its insulation properties.
If no-load loss, but the insulation resistance (between the coil, coil and buckle core) normal transformer, for its possible poor core quality, iron loss, or the coil has a partial short circuit test, you can use the short circuit test Instrument, etc. to check, remove the fault and then continue to use. If it is clear that occurs in the transformer internal disconnection, short circuit and other failures, you must remove the transformer for repair, you can follow the steps below.
The first step to dismantle the iron core. Transformers are often infused with asphalt, wax and other materials, should be heated before dissolution to melt away from the transformer, the transformer should be soldered off the terminals from the terminal, remove the fixed splint, pry with a screw to pry the first sheet of silicon steel, and then pliers Pull out the silicon steel pieces one by one. Take out the silicon steel, you must be careful not to damage the coil leads, while avoiding the silicon steel break and bend. Then, take out the silicon steel together, wrapped in paper, so as to avoid loss and damage to the insulation.
The second step to remove the coil. Remove the core, the first appearance of the coil for a check to see the appearance of non-destructive, and then again with the insulation resistance table to check what the fault occurred in a coil for disassembly purpose. Take note of the removal of the interlayer insulation, wire diameter, the number of layers and layers, etc., in order to re-winding reference. At the same time, care should be taken to protect the skin of the wire varnish for reuse; special attention must also be paid to find and find out why the coil is shorted and open. When you find the fault site and processed, according to the original winding method re-winding, and after winding and repair, to conduct a comprehensive test and inspection. After the indicators are in line with the requirements, can continue to use.
Precautions
When the transformer winding short circuit, the phenomenon is that the transformer temperature is too high, there is coke smell, smoke, the output voltage decreases, the output voltage is unstable. If you find these phenomena, you should immediately cut off the power, check.
Short circuit due to the main reasons: the transformer damp internal mold, over time will make the insulation damage, resulting in serious leakage or short circuit; or due to the aging of the transformer insulation aging, insulation performance decreases, causing insulation breakdown, resulting in short circuit. In addition the sudden increase in supply voltage can also cause insulation breakdown, winding short circuit.
