电机的软启动（Soft start of motor）
What is the soft start of the motor? What are the characteristics?
可行性分析的四个方面The soft start of an electric motor has the following characteristics compared with other conventional methods of starting:
1, in the starting process of the motor stepless voltage from the initial value of up to the total pressure, the torque of the motor has a uniform increa in the process of starting, the motor starting characteristics of "soft", so called soft start.
2. Limit the starting current of the motor and adjust the starting current according to the load characteristics.
3, starting voltage adjustable, in the t time, the motor speed increas gradually, to avoid the impact of speed.
Is the frequency conversion soft start? What other ways?
Variable frequency starting should also belong to soft start, but frequency converter is much more functional than soft starter.古人名言名句
跑步机排行榜Learn the principles of the motor, you should know, the speed of the motor with frequency, voltage, current relationship. It is not difficult to understand the working principle of the inverter
Soft start is relative to full voltage startup
So what kind of startup is soft start? It's like star triangle starting, isn't it?
Motor start, full voltage start and step-down start
The starting voltage of cage motor is resistance voltage reduction, lf coupling voltage reduction, star delta conversion and contactless buck start
第九课堂Resistance to step-down, larger loss, basically eliminated. Second, there is an instantaneous loss of pressure in the third conversion process.
Soft starters should be part of a contactless buck start (personal view), in which the start-up process is smooth, the voltage ris from low to high, and the characteristics are soft, so it is called soft start.
In practice, silicon is ud to regulate the voltage. The voltage ris from low to high, and does not produce much starting current. It is good for the power grid.
Star delta and lf coupling voltage step-down is starting, but they are classified to surge, star delta is divided into two grades, 220 and 380, since the lotus buck regulator file share point, soft starting is stepless pressure regulation to u scr.
With the frequency conversion speed is different, is not
required, the soft start frequency.中国主要河流
The soft starter adjusts only the voltage, and the f remains the same, using a special soft starter;
Variable frequency starting U / F constant, using frequency converter, four pairs of opinions.
什么颜色No textbooks, shit Y-delta what is out of date.
The idea is that the soft start is mainly to mitigate the momentary fluctuations of the power supply, as well as to protect the motor, and also to protect the pump or other motors when it stops.
Soft starter is mainly ud in start and stop; frequency converter is mainly ud for speed control, but he can also realize soft start function, of cour, the price is more expensive!
Originally, knowledge is accumulated by this way
Bad on the soft starter is connected between the power supply and controlled motor, control the turn-on angle of thyristor, the motor input voltage from zero to a pret function incread gradually, until the end of starting, the motor is given full voltage soft starter, soft starter in the process of the motor starting torque increas gradually, speed incread gradually. The soft start has the following veral kinds of starting methods generally.
(1) ramp soft start. This mode of starting is the simplest, and does not have the current clod loop control, only adjusts the thyristor conduction angle, caus it and the time certain function relations to increa. The disadvantage is that, due to the no current limit, the motor will start to produce a larger impact current in the process of starting the motor, which makes the thyristor damage and has a great impact on the power grid.
北大最帅双胞胎(2) constant current soft starting of slope. This mode of starting is in the initial stage of the motor starting, the current increas gradually, and when the current reaches the pret value, it is kept constant (T1 to T2 stage) until the start is completed. During starting, the rate of change of current ri can be adjusted according to the motor load. When the current ri rate is large, the starting torque is large and the starting time is short.
The starting mode is the most widely ud method of starting, especially for the starting of fans and pumps.云南印象
(3) step start. Boot, that is, in the shortest possible time, so that the starting current quickly reached the t point, that is, step start. By adjusting the tting value of the starting current, the fast starting effect can be achieved.
(4) pul shock starting. At the start of the starting stage, let the thyristor in a short time, with a larger current for a period of time after the fall, and then t up according to the original linear ri, connected to constant current start.
The starting method is less applied in general load, and is
suitable for heavy load and needs to overcome the starting condition of larger static friction.
The soft starter is actually a thyristor AC voltage regulator. By changing the trigger angle of the thyristor, the output voltage of the thyristor voltage regulating circuit can be adjusted. During the whole starting process, the output of the soft starter is a smooth step-up process (and can have current limiting function) until the thyristor is fully conducted and the motor operates at rated voltage.
"Soft start" not only can greatly reduce the transmission system impact of the start key to extend the rvice life of the parts, but also greatly shorten the time of the motor starting current impact, reducing the thermal shock load on the motor and the impact on the grid, so as to save energy and prolong the working life of the motor. In addition, through the u of "soft start" technology, in the lection of motors will be able to choo a smaller capacity of the motor, which can also reduce unnecessary equipment investment
The soft start of an electric motor has the following characteristics compared with other conventional methods of starting:
1, in the starting process of the motor stepless voltage from the initial value of up to the total pressure, the torque of the motor has a uniform increa in the process of starting, the motor starting characteristics of "soft", so called soft start.
2. Limit the starting current of the motor and adjust the
