Common troubleshooting of the hottest crane motor

2022-08-15
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Common troubleshooting of crane motor

common troubleshooting of crane motor: bearing noise when the motor is running, you must pay attention to the culture of bearing sound. Touch one end of the screwdriver on the bearing cover and the other end on the ear. You can hear the sound changes inside the motor, different parts, different faults, and different sounds. Such as creak, which is caused by the irregular movement of the rolling gun in the bearing, and is related to the clearance and grease state of the bearing. The hissing sound is the sound of metal friction, which is generally caused by the lack of oil in the bearing. The bearing should be disassembled and greased

AC motor will inevitably fail due to friction, vibration, insulation aging and other reasons during operation. If these faults are checked, found and eliminated in time, accidents can be effectively prevented

I. fault inspection of asynchronous motors

1. listen to the sound and carefully find the fault point. During the operation of AC asynchronous motors, if you find a thin buzzing, there is no change from high to low SAMPE Shanghai Branch, which is a normal sound. If the sound is thick, and there is a sharp buzzing and hissing sound, it is the precursor of failure, The following reasons should be considered:

(L) the vibration of the loose iron core motor during operation and the change of temperature from high to low will deform the fixing bolts of the iron core, resulting in the loosening of silicon steel sheets and large electromagnetic noise

(2) rotor noise the sound made by the rotation of the rotor, which is generated by the cooling fan, is a kind of purring sound, with a thump like that when the drum is beating. This is caused by the loose fit between the rotor core and the shaft caused by the acceleration torque of the motor under the speed change conditions such as sudden start, stop, reverse braking, etc. the light one can continue to be used, and the heavy one can be disassembled for inspection and repair

(3) bearing noise during the operation of the motor, attention must be paid to the culture of bearing sound. Touch one end of the screwdriver on the bearing cover and stick the other end to the ear. You can hear the sound changes inside the motor, different parts, different faults, and different sounds. Such as creak, which is caused by the irregular movement of the rolling gun in the bearing, and is related to the clearance and grease state of the bearing. The hissing sound is the sound of metal friction, which is generally caused by the lack of oil in the bearing. The bearing should be disassembled and greased

2. Using bromine sense, it is analyzed that there is no peculiar smell in the normal operation of the faulty motor. If strange smell is smelled, it is a fault signal, such as burnt smell, which is emitted by the barbecue of insulation, and with the increase of motor temperature, it will smoke in serious cases; For example, the smell of oil burning is mostly due to the lack of oil in the bearing and the peculiar smell caused by the evaporation of oil and gas when it is close to the dry grinding state

3. use the hand feeling to check the fault. Touch the TV shell with your hand to roughly judge the temperature rise. If you touch the motor shell with your hand and feel very hot, the temperature value is very high, you should check the reasons, such as heavy load and high voltage, and then eliminate the fault according to the reasons

II. Causes of common faults

1. The motor has no starting torque, or cannot be started under no-load, and makes abnormal sound. Cause: (L) one phase of the three-phase power supply circuit (including knife switch and lead stator winding) is powered off, causing single-phase startup. (2) The power supply voltage is too low. (3) The bearing is excessively worn, which makes the rotor close to the side of the stator, resulting in the non concentricity of the stator and the rotor and uneven air gap

2. the starting torque of the motor is small, and it cannot be started when it is loaded. When the load of the adhesive solution for future industry needs increases, the motor stops, sometimes makes a strong noise, and local heating. Cause: the electric voltage is low, the winding has inter turn short circuit, there is wire break or desoldering in the rotor winding, and one phase wire break after startup causes single-phase operation

3. the starting current is large, unbalanced and loud, causing the protective device to act and cut off the power supply. Cause: the stator winding wiring can reduce fuel consumption and carbon dioxide emission at the same time. The method may be incorrect, and the winding insulation to ground is aging

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