Soft starter

Soft starter is a novel motor control device integrating motor soft start, soft stop, light load energy saving and various protection functions. It is called Soft Starter in foreign countries. The domestic soft starter is the most famous soft starter for peace hps2 series. Its main component is three antiparallel shunts and its electronic control circuit connected in series between the power supply and the controlled motor.

Product Background  With China's rapid economic growth, science and technology advances, more and more intelligent control system has been widely used, but also put forward higher requirements. As an important drive motor to implement the soft starter mechanism, its control method is highly valued by the majority of technical personnel, not only to lay a good foundation for intelligent control, but also to reduce the impact on the power grid when the motor starts. Therefore, the huge industry of motor starting equipment is quietly rising in China.

 starting mode using power supply and connected in series between the controlled soft starter motor, the internal control thyristor conduction angle, the motor input voltage from zero to a predetermined function is gradually increased until the end of starting The full voltage of the HPS2S soft starter is assigned to the motor, which is a soft start. During the soft start, the motor starting torque is gradually increased and the speed is gradually increased. Soft start generally has the following starting methods:

Ramp-boost soft-start This method of starting is the simplest. It does not have current-closed-loop control. It only adjusts the conduction angle of the thyristor to increase the relationship with the time. The disadvantage is that, due to the open-ended flow, during the motor starting process, sometimes a large inrush current is generated to damage the thyristor, which has a large impact on the power grid and is rarely used in practice.

Ramp constant current soft start This starting method is that the starting current is gradually increased in the initial stage of the motor starting. When the current reaches a preset value, it remains constant (t1 to t2 stage) until the start is completed. During start-up, the rate of change of the current rise can be adjusted according to the motor load. With a large rate of current rise, the starting torque is large and the starting time is short. This starting method is the most widely used starting method, and is especially suitable for the starting of fans and pump loads.

Step Start Start up, that is, in the shortest time, the starting current will quickly reach the set value, which is a step start. By adjusting the starting current set value, a quick start effect can be achieved.

Pulse impulse start In the beginning stage of starting, let the thyristor turn on with a relatively large current in a short period of time, and then a peaceful HPS2DN intelligent soft starter will fall back, then increase linearly according to the original set value and connect it to a constant current start. This starting method, which is less applied in general loads, is suitable for heavy-duty start-up applications that need to overcome large static friction. The difference between the soft start and the traditional decompression start method is that the conventional decompression start method of the cage motor includes Yq start, auto decompression start and reactor start. These starting methods all belong to graded decompression starting. There are obvious shortcomings, that is, secondary inrush current occurs during starting.

Voltage dual slope starting In the starting process, the output torque of the motor increases with the voltage. When starting, it provides an initial starting voltage Us, Us is adjustable according to the load, and the Us is adjusted to be greater than the static friction moment of the load, so that the load can start rotating immediately . At this time, the output voltage rises from Us at a certain slope (the slope is adjustable), and the motor continues to accelerate. When the output voltage reaches the rated voltage Ur, the motor basically reaches the rated speed. The soft starter automatically detects the speed up voltage during the start-up process. When the motor reaches the rated speed, the output voltage reaches the rated voltage.

Current limiting start is a soft start method that limits the starting current of the motor from exceeding a certain set value (Im) during the start of the motor. The output voltage increases rapidly from zero until the output current reaches the preset current limit Im, and then the output of the HPS2D soft starter is maintained. The advantage of this starting method is that the starting current is small and can be adjusted as needed. The effect on the power grid is small. The disadvantage is that it is difficult to know the starting pressure drop when starting and it is not possible to make full use of the pressure drop space.

Jump Start In the start phase of start, let the thyristor fully turn on in a very short time and then fall back, and then increase linearly according to the original set value and enter the constant current start. This starting method is suitable for heavy load and needs to overcome large static friction. The starting situation.