The cause of the motor heating
4. The power supply voltage is high, the excitation current increases, and the motor will overheat.
Excessive voltage can jeopardize motor insulation and put it at risk of breakdown. When the power supply voltage is too low, the electromagnetic torque will decrease. If the load torque is not reduced, the rotor rotation number is too low. At this time, the increase of the slip rate will cause the motor to overload and generate heat. Long-term overload will affect the life of the motor. When the three-phase voltage is asymmetrical, that is, when the voltage of one phase is high or low, it will cause the current of a certain phase to be too large, the motor will heat up, and at the same time, the torque will be “beep” when the torque is reduced, and the winding will be damaged if the time is long.
In short, whether the voltage is too high, too low or the voltage is asymmetrical will increase the current, the motor will heat up and damage the motor. Therefore, according to national standards, the motor power supply voltage should not change by more than ±5% of the rated value, and the motor output power can be maintained at the rated value. The motor supply voltage must not exceed ±10% of the rated value. The difference between the three-phase supply voltage should not exceed ±5% of the rated value.
5, winding short circuit, turn-to-turn short circuit, phase-to-phase short circuit and winding open circuit
After the insulation between two adjacent wires in the winding is damaged, the two conductors are collided, which is called a winding short circuit. A short circuit in a winding that occurs in the same winding is called a turn-to-turn short circuit. A winding short circuit occurring between two phase windings is called an interphase short circuit. Either way, it will increase the current of one phase or two phases, causing local heating, causing insulation aging to damage the motor. Winding open circuit is a fault caused by the stator or rotor winding of the motor being broken or blown. Whether the winding is short-circuited or open circuit may cause the motor to heat up or even burn out. Therefore, this situation must be stopped immediately after this happens.
6. The material leaks into the motor to reduce the insulation of the motor, thus allowing the motor to lower the temperature rise.
When solid materials or dust enters the motor from the junction box, it will reach between the stator and rotor air gaps of the motor, causing the motor to sweep until the motor winding insulation is worn out, causing the motor to be damaged or scrapped. If liquid and gaseous media leak into the motor, it will directly cause the motor insulation to drop and trip. Generally, liquid and gas leaks have the following manifestations:
Various container and delivery pipe leaks, pump seal leaks, flushing equipment and floors;
After the mechanical oil leaks, enter the motor from the gap of the front bearing housing;
The oil seals such as reducers connected to the motor wear, and the mechanical lubricating oil enters along the motor shaft. After accumulating inside the motor, the motor insulation paint is dissolved, so that the insulation performance of the motor is gradually reduced.
If you want to buy a vacuum cleaner motor, please pay attention to High Speed Vacuum Cleaner Motor.
