Most motors are of the squirrel cage type. If they are used to generate electricity, then it is just the residual magnetism. Basically, there is no generation, and only 3% of the styles;
If you use wire winding When using a rotor motor to generate electricity, the excitation current is not easy to match, but the power generation performance is much better. In terms of percentage, it depends on the excitation situation. It can be as close as 50%.
It is not recommended to use an electric motor as a generator because the design concept is different and it is unreasonable to use it as a substitute.
It is recommended that if the generated power is not large, you can choose a permanent magnet generator; if the power is large, use a brushless generator.
What I compiled: Low-voltage three-phase asynchronous motor fault finding 2011-11-07 12:55
The motor can start, but stops after turning
There are three possibilities:
First, the starting torque of the motor is too large (usually caused by mechanical jamming, you have to look at the specific situation), causing the low-voltage comprehensive protection or thermal relay to operate;
The second is that the self-protection contact of the contactor cannot be closed normally;
The third is that the motor winding or cable is grounded or short-circuited, causing the air switch to trip.
The motor makes abnormal noises when running.
1. Causes of failure: ① The rotor rubs against the stator insulating paper or slot wedge; ② The bearing is worn or there are foreign matter such as sand in the oil; ③ The stator and rotor core is loose; ④ The bearing is short of oil; ⑤ The air duct is filled or the fan wipes the cover, ⑥ The stator and rotor Iron cores rub against each other; ⑦The power supply voltage is too high or unbalanced; ⑧The stator winding is misconnected or short-circuited.
2. Troubleshooting: 1. Trim the insulation and lower the groove wedge; 2. Replace the bearings or clean the bearings; 3. Inspect the stator and rotor cores; 4. Add oil; 5. Clean the air duct; reinstall the device; 6. Eliminate scratches and install the small rotor in the car if necessary; ⑦ Check and adjust the power supply voltage; ⑧ Eliminate stator winding faults.
The motor vibrates greatly during operation
1. Causes of failure: ① Excessive bearing clearance due to wear; ② Uneven air gap; ③ Unbalanced rotor; ④ Bent shaft; ⑤ Iron core deformation or looseness; ⑥ Coupling (pulley) center is not corrected; ⑦ Fan is unbalanced; ⑧ Machine The shell or foundation is not strong enough; ⑨ The motor anchor screws are loose; ⑩ The cage rotor is welded and broken; the winding rotor is broken; and the stator winding is faulty.
2． Troubleshooting: ①Inspect the bearings and replace them if necessary; ②Adjust the air gap to make it uniform; ③Correct the dynamic balance of the rotor; ④Straighten the rotating shaft; ⑤Correct the overlapping iron core; ⑥Recalibrate to make it meet the regulations; ⑦Inspect the fan and correct it Balance and correct its geometry; 8. Reinforce; 9. Tighten the anchor screws; 10. Repair the rotor winding; repair the stator winding.
In actual operation, the common faults of the motor mainly include the following:
1. The motor cannot start
The reason why the motor cannot start is mainly due to the power supply. It is not connected, the load is too large, the rotation is blocked, the fuse is blown, etc. At this time, you must first check the power circuit or additional electrical components, mainly to ensure that the circuit switch is intact.The wiring is correct and there is no reverse connection or short circuit. Secondly, check the load and mechanical parts to determine whether the bearings are damaged, whether the driven machinery is stuck, and whether the gap between the stator and the rotor is abnormal, causing the stator and the rotor to collide.
2. The motor shell is charged
The motor shell is charged because the motor ground wire is disconnected or loose, and the lead wire touches the junction box or the wiring board has too much grease. The solution is to check And connect the ground wire, check the junction box, and clean the wiring board.
3. Motor overheating
When the motor is overloaded, runs out of phase, or the motor ventilation duct is blocked, it will cause the motor to overheat. When the motor is overloaded, the current will increase, causing serious overheating of the motor and possibly burning out the motor. At this time, the load must be adjusted in time to avoid long-term overload operation of the motor.
As long as one phase of the three-phase power supply is open circuit, it will cause the motor to run with phase loss. If the phase loss operation time is too long, the motor will be burned out. Therefore, check the power circuit frequently.
Too much sludge and dust in the motor, and blockage of the motor ventilation duct will affect the heat dissipation effect and cause the motor to overheat. Therefore, obstructions must be removed in time to improve heat dissipation conditions.
4. The sound of the motor is abnormal
When the motor is running normally, the sound is uniform and noise-free. When the bearing is damaged or the phase is missing, it will make abnormal noise. Even a screeching sound.
Bearing damage is mainly caused by excessive bearing clearance or severe wear, lack of lubricating oil or improper selection of grease. At this time, the bearings need to be cleaned or replaced in time to ensure good lubrication of the motor during operation. After a general motor runs for about 5000 hours, the grease should be replenished or replaced.
When the motor is running without a phase, the speed will drop and make abnormal noise. If the motor is run for too long, the motor will be burned out. Phase loss operation is mainly caused by problems in the power circuit, such as one phase of the power line being disconnected, or one phase winding of the motor being disconnected. To prevent the motor from running due to phase loss, we must first pay attention to discovering the abnormal phenomena of phase loss operation and eliminate them in time. Secondly, important motors should be equipped with phase loss protection.
Abnormal sound when the motor is running may also be caused by the fan blades hitting the windshield. In this case, the windshield must be repaired in time.