The entire set of magnetic steel in the motor should be replaced. The entire motor is replaced during the repair process. 3. A non-touch infrared thermometer for motor heating, or a temperature measurement gear of a multimeter (multimeter with temperature measurement). When the temperature of the motor end cover exceeds 30 ℃ above the ambient temperature, it indicates that the temperature rise of the motor has exceeded Normal range, the temperature rise of the general motor is below 25 ℃. The direct cause of motor heating is caused by large current. The motor current i, the motor's input electromotive force E1, the motor's induced electromotive force (also known as back electromotive force) E2, and the relationship between the motor coil resistance R are: i = (E1-E2) \u0026 divide; Ri increases, clarifies R Becomes smaller or E2 decreases. R decrease is usually caused by a short circuit or an open circuit of the coil. E2 reduction is generally caused by the demagnetization of the magnetic steel or caused by the short circuit or open circuit of the coil. In the repair practice of the entire vehicle of an electric vehicle, the fault of the motor heating is usually dealt with by replacing the motor. 4. There is mechanical bump or mechanical noise when the motor is working. Regardless of whether the high-speed motor is still a low-speed motor, it should not show mechanical bumps or irregular mechanical noise during load operation. 5. Brushless motor phase loss Brushless motor phase loss is generally caused by damage to the Hall element of the brushless motor. We can measure the resistance of the Hall element output lead relative to the Hall ground and the Hall power lead using The comparison method determines which Hall element is faulty. In order to ensure the accurate commutation orientation of the motor, it is generally advisable to replace all three Hall elements at the same time. Before replacing the Hall element, it is necessary to find out whether the phase algebraic angle of the motor is 120 degrees or 60 degrees. Generally, the orientation of the three Hall China electric motors manufacturers elements of a 60-degree phase angle motor is parallel. For a 120-degree phase angle motor, one Hall element at the center of the three Hall elements is placed in a 180-degree orientation. Analysis of common motor faults and countermeasures Low-voltage three-phase communication motors (hereinafter referred to as motors) have the advantages of simple structure, cheap price, and convenient repair. Therefore, it is widely used in the drag equipment of industrial and agricultural machinery and equipment, and it is the most widely used of all motors. In spite of this, in the actual work of the motor will inevitably occur various failures. The following is an analysis of the causes of common failures of motors and their countermeasures, for reference by colleagues. First, the motor temperature rises too high or smoke This fault is the performance of the motor overheating. There are many reasons: both external factors of the motor (such as poor power supply quality, excessive load, high ambient temperature, poor ventilation, etc.); and the motor itself. Common causes and countermeasures of the motor itself: 1. The winding connection is wrong, and the star is wrongly connected into a triangle or vice versa. 2. The stator windings are short-circuited or grounded between turns or phases, which increases the current and adds copper loss. If the fault is not severe, only heavy insulation is required, and the winding should be replaced in severe cases. 3. The winding of one phase of the stator is broken, or one of the branches of the parallel winding is broken, which causes the three-phase current to be unbalanced and the winding to overheat. 4. Broken rotor bar. Weld or repair copper rod rotors, and replace cast aluminum rotors. 5. The stator and rotor are rubbed. You can check whether the bearing is loose, whether the stator and rotor are defective. 6. The ambient temperature is high, the motor has a lot of dirt on its surface, or the ventilation duct is blocked; 7. The motor fan is faulty and the ventilation is poor; 2. Overheating of the bearing When the temperature of the rolling bearing of the motor exceeds 95 ° C and the temperature of the sliding bearing exceeds 80 ° C, the bearing is overheated. The reasons and countermeasures are as follows: 1. Damaged bearings should be replaced with new ones. 2. Too little, too much, or impurities such as iron filings. The volume of grease should not exceed 70 of the volume of bearings and bearing caps, and should be renewed when there are impurities. 3. The bearing cooperates with the end cap too tightly or too loosely. The bearing chamber is machined when it is too tight, and a steel sleeve is inserted into the end cap when it is too loose. 4. Defective motor end cap or bearing cap assembly. Flatten the end cap or bearing cap opening and tighten the screws. 5. The drive belt is too tight or the coupling device is defective. Adjust the belt tension and proof the coupling. 6. There is too little lubricating oil in the sliding bearing, there are impurities or the oil ring is stuck, it should be refueled, replaced with new oil, repaired or replaced. 7. The bearing clearance is too large or too small; 8. The motor shaft is tortuous. Third, the noise is abnormal 1. When the stator and the rotor are rubbed, a sharp 'scratch' sound will occur. The bearing should be checked, and the damage needs to be updated. If the bearing is not damaged, it can be found that the bearing is walking inside or outside Insert or replace bearings and end caps. 2. The motor is working in the absence of phase, and the roar is particularly loud. You can turn off the power and then turn it on to see if it can start normally again. If it cannot start, there may be a phase disconnection. If the head is not connected, phase loss will occur. 3. When the bearing is severely lacking oil, you can hear '咝 咝' sound from the bearing room. Bearings should be cleaned and refilled. 4. The wind blade hits the shell or there is debris, and it will announce the impact sound. The blades should be proofread to eliminate debris around the blades. 5. The rotor guide bar cracks, and the 'buzzing' sound that is high and low at the time of the onset also slows down the speed and increases the current. 6. The wiring at the beginning and end of the stator winding is wrong, there is a low roar, and the speed also decreases. 7. Stator 2. Rotor core is loose; 4. Excessive vibration 1. The motor rotor is unbalanced (for example, the weight screw on the rotor is dropped). The dynamic balance should be checked. 2. The drive belt wheel is unbalanced and the static balance should be checked. 3. The twisting shaft should be replaced. Rotary shaft, or car straight bushing (hot jacket). 4. The base of the equipment is uneven or fixed. The equipment should be re-installed and fixed stably. 5. The rotor guide bar is cracked, causing the load current to vibrate in large and small amounts. 6. Coupling The device is incorrect or loose. 7. The driven machine loses its dynamic balance. 8. The stator winding has some faults and the rotating magnetic field is unbalanced to cause vibration. 9. The bearing gap is too large due to wear; 10. The core is deformed or loose; 11 The electric fan is unbalanced; five, the three-phase current imbalance is formed during the work 1. The three-phase power voltage is severely unbalanced (that is, not equal). For example, the switch contacts are badly touched. 2. One of the three-phase windings is open circuit or one-phase melting. Phase failure 3. There is a partial short circuit between the turns or phases of the winding, and the fuse is not broken. 4. A parallel branch or several parallel branches of a certain group of three-phase windings are broken, forming three-phase impedances that are different. 5. Three The stator and winding of one phase are wrong and the fuse is not blown. 6. When the motor is operating, the ammeter pointer swings back and forth. This failure may be caused by a broken rotor guide bar. 7. The motor speed becomes lower 1. Power supply voltage Too low, you should check and find out the reason. 2. The rotor guide bar is cracked or de-soldered, and the broken bar should be checked and repaired. 3. The stator winding connection is wrong, you should check and correct the connection method.
