Why does the motor appear serious scald phenomenon?

2020-09-02 10:49

According to the motor manufacturer's editor, the air gap is generally 0.2 mm ~ 1.5 mm in small and medium-sized motors. When the air gap is large, the exciting current needs to be very large, which will affect the power factor of the motor. If the air gap is too small, the rotor may have friction or collision. Usually, due to the serious bearing out of tolerance and wear and change in the bearing seat inner hole The bearing block, end cover and rotor are different from each other on the axis, which may lead to hole scanning and easily cause the motor to heat or even burn out. If the bearing is found to be worn, it should be replaced in time. The end cover should be replaced or brush plated. The relatively simple treatment is to set the end cover. What are the other reasons?

1. Abnormal vibration or noise of motor may lead to motor heating: this kind of situation belongs to the vibration of motor itself, which is mostly due to poor dynamic balance of rotor, bending of bearing, shaft, end cover, frame, rotor axis, looseness of fasteners or unevenness caused by motor installation foundation, installation fails to reach the designated position, or mechanical side passes through, which needs to be excluded situation.

2. Abnormal bearing operation will definitely lead to motor heating: whether the bearing works normally can be judged by hearing and temperature experience. The bearing end can be tested by hand or thermometer to determine whether the temperature is within the normal range. If the impact sound is heard, it means that one or more ball bearings may be crushed. If a hissing sound is heard, it means that the bearing lubricating oil is insufficient The motor should replace the grease for 3000 hours to 5000 hours.

3. Winding short circuit, turn to turn short circuit, phase to phase short circuit and winding open circuit: when the insulation between two adjacent wires in the winding is damaged and the two wires collide, it is called winding short circuit, the winding short circuit in the same winding is called turn to turn short circuit, and the winding short circuit between two windings is called phase short circuit. No matter which one of them will increase the current of one or two phases and cause local heating The motor is damaged by aging insulation. Winding disconnection refers to the fault caused by the stator or rotor winding damaged due to collision or combustion. The short circuit or open circuit of winding may cause the motor to heat or even burn out. Therefore, this situation needs to be stopped immediately.

4. If the power supply voltage is too high, the excitation current will increase, and the motor will produce too much heat: high voltage will endanger the insulation of the motor, so there is a risk of breakdown. When the power supply voltage is too low, the electromagnetic torque will be greatly reduced. If the load torque is not reduced and the rotor speed is too low, the increase of slip will lead to motor overload and heating, and long-term overload will affect the motor Service life: when the three-phase voltage is asymmetric, that is, when the single-phase voltage is on the high side or the low side, it will cause over-current in a certain phase, and the motor will generate heat. At the same time, when the torque is reduced, there will be a "buzz" sound. If the time is long, the winding will be damaged.

The above is about why the motor will appear serious scalding phenomenon, if there is anything else you don't know, you can communicate with our customer service, we will serve you wholeheartedly.