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电动机启动故障有哪些原因

  • 发布日期:2021-07-10 总浏览:





电动机启动故障有哪些原因


三相异步电动机一相或两相绕组烧毁(或过热)的原因;

       如果出现电动机一相或两相绕组烧坏(或过热),一般都是因为缺相运行所致。当电机不论何种原因缺相后,电动机虽然尚能继续运行,但转速下降,滑差变大,其中B、C两相变为串联关系后与A相并联,在负荷不变的情况下,A相电流过大,长时间运行,该相绕组必然过热而烧毁。为三相异步电动机绕组为Y接法的情况:电源缺相后,电动机尚可继续运行,但同样转速明显下降,转差变大,磁场切割导体的速率加大,这时B相绕组被开路,A、C两相绕组变为串联关系且通过电流过大,长时间运行,将导致两相绕组同时烧坏。

特殊情况下,如果停止的电动机缺一相电源合闸时,一般只会发生嗡嗡声而不能启动,这是因为电动机通入对称的三相交流电会在定子铁心中产生圆形旋转磁场,但当缺一相电源后,定子铁心中产生的是单相脉动磁场,它不能使电动机产生启动转矩。因此,电源缺相时电动机不能启动。但在运行中,电动机气隙中产生的是三相谐波成分较高的椭圆形旋转磁场,所以,正在运行中的电动机缺相后仍能运转,只是磁场发生畸变,有害电流成分急剧增大,最终导致绕组烧坏。

相应对策:无论电动机是在静态还是动态,缺相运行带来的直接危害就是电机一相或两相绕组过热甚至烧坏。与此同时,由于动力电缆的过流运行加速了绝缘老化。特别是在静态时,缺相会在电机绕组中产生几倍于额定电流的堵转电流。其绕组烧坏的速度比运行中突然缺相更快更严重。所以在我们对电机进行日常维护和检修的同时,必须对电机相应的MCC功能单元进行全面的检修和试验。尤其是要认真检查负荷开关、动力线路、静动触点的可靠性。杜绝缺相运行。

     总之,无论是从事电气的工作人员或是管理人员,都要从实际出发,切实落实好设备的维护与维修。

     使用河北西玛电机智能电机,可以有效防止过载缺相烧毁电机的情况,欢迎新老客户积极选购!!!

What are the causes of motor starting failure

What are the causes of motor starting failure

Three phase asynchronous motor one phase or two phase winding burning (or overheating) reasons;

If one phase or two-phase winding of motor is burnt out (or overheated), it is generally caused by phase missing operation. When the motor is short of phase for any reason, the motor can continue to run, but the speed drops and the slip becomes larger. The B and C phases become series connection and then parallel with the a phase. Under the condition of constant load, if the a phase current is too large and runs for a long time, the phase winding will be overheated and burned. It is the case that the winding of the three-phase asynchronous motor is Y-connected: the motor can continue to run after the power supply is lack of phase, but the same speed drops obviously, the slip becomes larger, and the speed of the magnetic field cutting conductor increases. At this time, the B-phase winding is open circuit, the A and c-phase windings become series connection, and the current is too large. If the motor runs for a long time, the two-phase windings will burn out at the same time.

Under special circumstances, if the stopped motor is switched on without a phase power supply, it will only produce a buzzing sound and cannot be started. This is because when the motor is connected with symmetrical three-phase AC power, it will produce a circular rotating magnetic field in the stator core. But when the motor is short of a phase power supply, it will produce a single-phase pulsating magnetic field in the stator core, which can not make the motor produce starting torque. Therefore, the motor cannot be started when the power supply is out of phase. However, in operation, the elliptical rotating magnetic field with high three-phase harmonic component is generated in the air gap of the motor. Therefore, the motor in operation can still operate after phase loss, but the magnetic field is distorted and the harmful current component increases sharply, which eventually leads to the winding burn out.

Corresponding countermeasures: no matter the motor is in static or dynamic state, the direct harm brought by the lack of phase operation is that one or two-phase windings of the motor overheat or even burn out. At the same time, the over-current operation of power cable accelerates the insulation aging. Especially in the static state, the open phase will produce locked rotor current several times of the rated current in the motor winding. The speed of winding burning out is faster and more serious than the sudden phase loss in operation. Therefore, when we carry out the daily maintenance and overhaul of the motor, we must carry out a comprehensive overhaul and test on the corresponding MCC functional units of the motor. Especially, the reliability of load switch, power line, static and dynamic contact should be carefully checked. Put an end to open phase operation.

In short, whether engaged in electrical staff or management personnel, should proceed from reality, and effectively implement the maintenance and repair of equipment.

The use of Hebei Xima motor intelligent motor, can effectively prevent the overload phase burning motor, welcome new and old customers to actively choose!!!

What are the causes of motor starting failure

Three phase asynchronous motor one phase or two phase winding burning (or overheating) reasons;

If one phase or two-phase winding of motor is burnt out (or overheated), it is generally caused by phase missing operation. When the motor is short of phase for any reason, the motor can continue to run, but the speed drops and the slip becomes larger. The B and C phases become series connection and then parallel with the a phase. Under the condition of constant load, if the a phase current is too large and runs for a long time, the phase winding will be overheated and burned. It is the case that the winding of the three-phase asynchronous motor is Y-connected: the motor can continue to run after the power supply is lack of phase, but the same speed drops obviously, the slip becomes larger, and the speed of the magnetic field cutting conductor increases. At this time, the B-phase winding is open circuit, the A and c-phase windings become series connection, and the current is too large. If the motor runs for a long time, the two-phase windings will burn out at the same time.

Under special circumstances, if the stopped motor is switched on without a phase power supply, it will only produce a buzzing sound and cannot be started. This is because when the motor is connected with symmetrical three-phase AC power, it will produce a circular rotating magnetic field in the stator core. But when the motor is short of a phase power supply, it will produce a single-phase pulsating magnetic field in the stator core, which can not make the motor produce starting torque. Therefore, the motor cannot be started when the power supply is out of phase. However, in operation, the elliptical rotating magnetic field with high three-phase harmonic component is generated in the air gap of the motor. Therefore, the motor in operation can still operate after phase loss, but the magnetic field is distorted and the harmful current component increases sharply, which eventually leads to the winding burn out.

Corresponding countermeasures: no matter the motor is in static or dynamic state, the direct harm brought by the lack of phase operation is that one or two-phase windings of the motor overheat or even burn out. At the same time, the over-current operation of power cable accelerates the insulation aging. Especially in the static state, the open phase will produce locked rotor current several times of the rated current in the motor winding. The speed of winding burning out is faster and more serious than the sudden phase loss in operation. Therefore, when we carry out the daily maintenance and overhaul of the motor, we must carry out a comprehensive overhaul and test on the corresponding MCC functional units of the motor. Especially, the reliability of load switch, power line, static and dynamic contact should be carefully checked. Put an end to open phase operation.

In short, whether engaged in electrical staff or management personnel, should proceed from reality, and effectively implement the maintenance and repair of equipment.

The use of Hebei Xima motor intelligent motor, can effectively prevent the overload phase burning motor, welcome new and old customers to actively choose!!!




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