one voltage
Reason: high voltage, will make the transformer overexcitation, the sound increased and sharp, direct serious impact on the noise of the transformer.
Judgment method: look at the low voltage output voltage first, not at the voltmeter on the low voltage cabinet, the voltmeter only plays an indicator role, should be measured with a multimeter.
Solution: now the 10KV voltage in the city is generally on the high side, the measurement of the low-voltage output voltage should be put in the appropriate gear. High voltage tapping direction up, low voltage voltage down; The tap direction decreases and the low voltage increases.
two Fans, enclosures, other parts
Reason: fan, shell, other parts of the resonance will produce noise, generally mistaken for the noise of the transformer.
1. Shell: press the aluminum plate (or steel plate) of the shell with your hand to see whether the noise changes. If there is a change, the shell is in resonance. 2, fan: with a long dry stick against the shell of each fan, to see whether the noise changes, such as changes in the fan in resonance. 3, other parts: with a long dry stick against each part of the transformer (such as: wheel, fan bracket, etc.), to see whether the noise changes, such as changes in the resonance of parts.
Solution: 1, see whether the shell aluminum plate (or steel plate) is loose, it is possible to step on the deformation when installation, need to tighten the screw of the shell, the shell of the aluminum plate fixed, the deformation of the part of correction. 2. To see whether the fan is loose, it is necessary to tighten the fastening bolt of the fan and pad a small piece of rubber between the fan and the fan bracket to solve the vibration problem of the fan. 3. If the transformer parts are loose, they need to be fixed.
3. The installation
Reason: installation is not good will aggravate the vibration of the transformer, increase the noise of the transformer.
Judgment method: 1, the transformer foundation is not firm or uneven (an Angle is suspended), or the floor is too thin. 2, using channel steel to put the transformer up, will increase the noise. 3, the transformer noise transmission is very far, through the structure of the building can be transmitted to more than 5 floors.
Solution: 1, the reason for the big noise to tell the user, carefully explain to the user, with the softening method to solve. 2. The installation unit shall transform the original installation mode. 3, in the transformer car under the shockproof rubber pad, can solve part of the noise.
Four. The environment
Cause: the operating environment affects the noise of the transformer, and the unfavorable environment increases the noise of the transformer by 3dB ~ 7dB.
Judgment method: 1. The transformer room is very large and empty, without other equipment, and there is echo. 2. The transformer is too close to the wall, less than 1 meter. Transformer on the corner, wall reflection noise and transformer noise superposition, so that the noise increases. 3, the original use of oil, change the dry change will affect the noise of the transformer. The reason is that the crude oil transformer chamber is relatively small, and there is a oil leakage chamber and a oil leakage hole, the transformer is like on a sound box.
Solution: 1, the reason for the big noise to tell the user, carefully explain to the user, with the softening method to solve. 2, indoor installation of sound-absorbing materials.
Five. Vibration of bus bridge
Cause: because side by side busbar has a large current through, because the leakage of magnetic field makes the busbar vibration. The vibration of the bus bridge will seriously affect the noise of the transformer, which will increase the noise of the transformer by more than 15dB. It is difficult to judge, and the general users and installation units will mistake it for the noise of the transformer.
Judgment method: 1, the noise changes with the load. 2. Use a wooden stick to push the bus bridge. If the noise changes, it is considered that the bus bridge is in resonance. 3. The bus bar vibrates in the bridge frame, and it is useless to top it with a wooden stick. Need to open the bus bridge cover plate, check whether the bus is fixed.
Solution: 1. It is mainly to destroy the conditions of the resonance of the bus bridge, tighten or loosen the hanger rod screws. 2. Open the cover plate of bus bridge and fix the bus. 3. Soft connection is adopted for low-voltage outlet. 4, please the manufacturer of bus bridge to solve. 5. Tell the user the reason for the big noise.
Six. Transformer core self resonance
Reason: there is electromagnetic attraction between the silicon steel sheet joints and laminates due to magnetic leakage.
Judgment method: 1, the transformer noise is too large, the normal noise is mixed with other noises. 2. Transformer noise becomes wavy.
Solution: 1, tighten the screw on the transformer, including clamp screws at both ends, through the heart of the screw, screw pad pressure nail wire. 2, in the transformer car under the shockproof rubber pad, can solve part of the noise.
Seven. Transformer coil resonance itself
Reason: when there is load current in the winding through, the vibration of the winding is caused by the magnetic flux leakage generated by the load current
Judgment method: 1. The noise of the transformer is relatively large and low. 2, when the load of the transformer reaches a certain point, the noise begins to appear, and sometimes there is no phenomenon.
Solution: 1, the pad will press the nail wire all tight again, increase the axial compression force of the coil. 2. Loosen all the nails on the pad, loosen all the bolts on the copper row and the zero line copper row, shake the low-voltage coil, shift the high-voltage coil 3 ~ 5 mm, and then tighten all the bolts.
Eight. load
Cause: the transformer voltage waveform distortion, noise.
Judgment method: 1, in addition to the noise of the transformer itself, but also mixed with "cluck, cluck" noise. Check whether the load is equipped with rectification equipment and frequency conversion equipment. 2, when put into a certain load (rectifier equipment) transformer noise becomes larger. 3, when the load of the transformer is capacitive current, the rise effect will be generated to increase the secondary voltage, and the iron core will produce large noise over excitation. 4, when the secondary side input capacitor compensation transformer noise increases.
Solution: 1, the reason for the noise to tell the user. Allow users to apply for additional harmonic reduction devices. 2. Replace the control part of rectifier equipment. 3. Tell the user the reason for the big noise. 4. Reactor is installed on the secondary side of transformer.
Nine. Transformer phase loss
Cause: the transformer can not be normally excited, resulting in noise.
Solution: 1, transformer power failure, check whether the power supply is missing a phase; 2, check whether the transformer high voltage fuse fuse a phase;
Ten. Poor contact
Reason: It is because the contact inside high pressure cabinet is bad cause. Second, the knife brake is not closed in place
Judgment method: the transformer gives off an intermittent and abnormal noise.
Solution: 1. Check the contacts and fuses of the high voltage cabinet and the whole high voltage circuit. 2, please the high pressure cabinet manufacturer to check.
Eleven, suspended potential
Cause: Transformer clip channel steel, nail bolts, pull plate and other parts are sprayed with blue paint, the parts are not very good contact, under the action of the electric field between the parts of the suspension potential discharge noise.
Judgment method: suspension potential discharge issued a very slight "squeak, squeak" sound, listen carefully to hear, users often mistakenly think it is a transformer high voltage or low voltage in the discharge.
Solution: 1, this discharge will not affect the normal operation of the transformer, to explain to the user, 2, can be in power outage maintenance will contact the bad place of paint scrape off, so that the transformer parts good contact.
Low voltage line grounding or short circuit
When the low voltage line grounding or a short circuit accident, the transformer will issue a "boom" sound; The closer the short circuit point is to the transformer, the more obvious the sound is. If the short-circuit point is near the transformer, the transformer will roar like a tiger.
Thirteen, transformer comparison
Reason: some users mentioned that the transformer produced by such and such units in such and such places is less noisy than our transformer.
Solution: 1, tell the user even if the same type of transformer produced by the same manufacturer, their noise is not the same. 2, tell the user different transformers, different use environment, transformer noise is not the same. 3, tell the user that the noise of the transformer we produce in such and such place is smaller than that of such and such unit.
Fourteen, the understanding of dry change
Reason: some users have used oil transformer before, the understanding of oil transformer is deeper, the first contact with dry transformer, that the noise of dry transformer and oil transformer should be the same,
Solution: tell the user that the noise of the oil is also very big, but it is filled with oil, and a layer of sealed iron shell is added outside, and the sound can not be transmitted out. The dry iron core is exposed outside, and a little sound will come out. Noise is an inherent characteristic of the transformer, and the level of noise will not affect the quality of the transformer.
There are many abnormal sound factors in the transformer, and the fault location is not the same. Only by accumulating experience can we make accurate judgments.
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