What are the common faults of three-phase asynchronous motors?1. The motor cannot be rotated when energized, and there is no overheating.
This phenomenon may be due to the fact that at least two phases of the power supply are not connected, there is a two-phase fuse in the fuse, the overcurrent relay protection current value is set low, or there is a control cabinet wiring error. At this time, the switch and the fuse need to be checked to ensure that there is no intermittent phenomenon, and whether the model and specification of the fuse meet the requirements of the normal start and operation of the motor also need to be judged, of course, according to the current parameters under the normal operation of the motor to adjust the setting value of the relay or confirm the wiring error, it can be corrected in time.
2. The three-phase current is unbalanced and the phase difference is large.
This phenomenon occurs mainly because the motor winds around when it is off the assembly line.
The number of turns of the coil is unequal or the winding is reversed, or in the offline process, due to the damage of the enameled wire, there is a short circuit between turns, or there is an imbalance in the power supply voltage. Therefore, after checking and confirming the error, it is necessary to rewind the generator winding, improve the error phenomenon of the reverse connection of the winding, and at the same time, check and measure the balance of the power supply voltage in time.
3. Three-phase current balance, but the value is higher than the rated value.
This phenomenon is mainly because when the motor is re-wired, the number of turns of the winding coil is less than that of the factory, and the power supply voltage is higher than the rated voltage value of the motor. Therefore, according to the requirements of the factory, do a good job of rearranging the winding winding to ensure that the power supply voltage can meet the actual rated value of the motor.
requirements, and do a good job in the improvement of the wrong operation wiring mode, re-equip the motor, you can ensure the uniformity of the stator and rotor clearance.
4. The casing is electrified.
When this happens, it is necessary to check whether the wiring joints are insulated and then dispose of them properly. Through the cause analysis, there may be: damage to the insulation of the notches at both ends of the tank;The insulation of the connector of the lead wire or junction box is damaged;The enclosure does not achieve reliability grounding;There are also iron filings and other debris in the tank, which are not cleaned up in time. In order to solve these problems, it is necessary to: wrap the insulating cloth or put on the insulating sleeve;Patiently look for the location of the insulation damage, then put on the insulating paper, and apply the film insulating paint correctlyThe joint position of each coil is disassembled one by one, and then the elimination method is used to do a local repair for the grounding coil.
5. The current does not exceed the rated value, but the motor temperature is too high.
In view of this phenomenon, it is necessary to do a good job of inspection and treatment, through analysis, the reason for this problem is: the motor is directly exposed to the sun;The ambient temperature is on the high side;There is more sludge and dust in the motor, which will affect the normal heat dissipationPoor ventilation. For this part of the problem, it is necessary to do the following: increase the facilities for shading;Appropriately reduce the environmental problem, or further reduce the use of motor capacity;Clean up the dust in time;Clean the air ducts, or simply remove all the things that affect the ventilation.