Pengetahuan permulaan motor elektrik lembut

Generally the current required to start the ac induction motor is much higher than the rated current, about 6 times the rated current.

At such a current, the electric motors will be subjected to greater shocks than during normal operation, which will increase the induction motor's losses, reduce ac electric motors life and even cause damage to other parts of the machine when the current is too high.

In such circumstances, people are beginning to attach importance to the study of soft starting of electric motors, hoping that the relevant technology will enable induction motor to start smoothly and gently.

1. The principle of electronic soft starter

Existing technology for soft starting of electric motor is mainly to control the smooth starting of three-phase AC asynchronous motors, through the use of three-phase AC asynchronous motors to achieve soft starting of ac induction motor and to provide protection for motor starting and stopping of motors.

Such technology is widely used in industry, where it has been used to good effect to replace the traditional Y/△ start.

The three-contrast shunt thyristor (SCR) regulates the voltage supplied of the soft starter and is the regulator of the soft starter.

When the SCR is connected to the circuit, it acts as a link between the full power supply and the motor stator.

When the smooth acceleration start is clicked, the starting voltage inside the thyristor gradually rises, and the motor will then slowly accelerate under the action of the full voltage.

When the running speed reaches the required full speed, the thyristor will achieve full conduction, at which point the voltage of the click is the same as the rated voltage.

This enables the soft start of the motor and is in line with the mechanical properties of the machine, and such a start allows the whole process to run smoothly.

In this way, the ac motor runs normally under the protection of the thyristor, allowing the electric motor to be subjected to smaller shocks and losses, which can significantly improve the service life of the induction motor and allow it to maintain good working conditions.

2. Soft start technology for asynchronous motors

2.1, Thyristor AC voltage regulated soft start

Thyristor AC soft starters is mainly through changing the connection of the thyristor, the traditional connection to the three windings, so that the thyristor power supply in parallel.

The thyristor soft starter is highly adjustable, so users can make appropriate adjustments to the electric motor according to their different needs and make the motor acceleration start in a way that is more suitable for their needs.

2.2. Prinsip pelarasan pemula lembut pengatur AC tiga fasa

Pemula lembut pengatur voltan AC tiga fasa menggunakan sepenuhnya lengkung ciri voltan AC untuk memulakan motor melalui ciri voltan AC, dan idea menggunakan lengkung ciri voltan AC untuk mencapai permulaan lembut untuk motor elektrik adalah idea utama pemula lembut motor.

Idea utama ialah menggunakan tiga pasang thyristor secara bersiri dengan perlindungan motor elektrik dan menukar masa pembukaan dengan mengawal saiz nadi pencetus dan sudut pencetus.

Dengan cara ini, input motor elektrik mengekalkan voltan talian yang mencukupi untuk mengawal permulaan motor elektrik.

Sebaik sahaja motor pemacu frekuensi berubah telah dimulakan, voltan awal akan berubah kepada voltan terkadar, di mana tiga kontraktor pintasan akan bersatu dan motor akan dapat berjalan pada grid.

3、The advantages of soft start over traditional start

"Soft start" can not only significantly reduce the start-up impact on the drive system itself and extend the service life of key components.

Tetapi juga sangat mengurangkan masa hentaman arus permulaan motor elektrik, mengurangkan beban kejutan haba pada motor elektrik dan kesan pada grid, sekali gus menjimatkan kuasa dan memanjangkan hayat kerja motor.

In addition, by using "soft start" technology, smaller capacity motors can be used in the selection of motors, thus reducing unnecessary investment in equipment.

Permulaan Star-delta bergantung pada menukar pendawaian belitan motor, dengan itu menukar voltan di mana motor bermula.

Voltan talian yang digunakan semasa permulaan dikurangkan supaya arus permulaan menjadi lebih kecil dan kesan pada bar bas dikurangkan.

Supaya penurunan voltan bekalan pada busbar semasa permulaan adalah dalam julat yang dibenarkan (memerlukan penurunan voltan busbar tidak lebih daripada 10% daripada voltan undian).

Ini mengurangkan kesan pada busbar.

Sebagai contoh, dalam kes 4 kumpulan pemula 36 kW, arus operasi normal motor 36 kW ialah kira-kira 70 A.

Arus mula terus adalah kira-kira 5 kali arus biasa, iaitu empat kumpulan motor 36 kW bermula pada masa yang sama dan arus yang diperlukan ialah 1400 A.

Permulaan delta bintang untuk keperluan grid adalah 2-3 kali arus biasa, keperluan untuk arus grid ialah 560-840A, tetapi permulaan untuk voltan akan mempunyai kesan yang agak besar, bersamaan dengan kira-kira 3 kali voltan biasa.;

And soft start for the grid requirements is also 2-3 times the normal current, that is, 560-840A, but the soft start for the voltage impact is about 10%, basically no big impact.

This will not have a major impact.

Sebarang pertanyaan mengenai motor elektrik, sila hubungi motor elektrik profesional pengilang dalam China seperti berikut:

Motor Dongchun mempunyai pelbagai motor elektrik yang digunakan dalam pelbagai industri seperti pengangkutan, infrastruktur, dan pembinaan.

Dapatkan jawapan segera.