Comparison of advantages and disadvantages of decompression start, soft start and variable frequency start
Decompression start, the common is the star-delta start, the disadvantage is that the starting torque is small, only suitable for no-load or light-load start. The advantage is that the price is cheap. Soft start, can set the start time and starting initial torque to achieve soft start and soft stop for the device, and can limit the starting current, the price is moderate. Variable frequency start, can start smoothly according to the set time, and let the equipment run at the set frequency, the price is higher. Soft start, frequency converter, decompression start performance principle comparison
1. The soft starter is a combination of the thyristor AC voltage regulation technology and the power factor control technology. It is realized by the thyristor voltage regulation to realize the soft start and soft stop of the motor, and does not have the speed regulation function. 2. The frequency converter is a motor control (speed regulation) device that converts the power frequency power source into another frequency by using the on/off function of the power semiconductor device. The motor is controlled by frequency conversion (the voltage also changes with frequency, such as v/f constant), which is a true high-efficiency speed regulation method with high efficiency. The frequency converter enables true soft start, soft stop and efficient speed regulation. 3, the general common way to start the decompression is auto-decompression start-up and Y-Δ start. The biggest advantage of auto-coupling decompression is that the starting torque is large. When the winding tap is at 80%, start. The torque can reach 64% of the direct start. And the starting torque can be adjusted by tapping. It is still widely used today. Y-Δ is suitable for applications where there is no load or light load starting. And compared to any other decompression starter, the structure is the simplest and the cheapest. In addition, the star-delta starting method has the advantage that when the load is light, the motor can be operated in star connection. At this time, the rated torque can be matched with the load, which can improve the efficiency of the motor and save power consumption. Soft start, frequency converter, decompression start comprehensive analysis 1, the price problem is naturally the most expensive inverter, Y-Δ, auto-coupling decompression start is relatively cheap. For projects with smaller investments, economics will be the first choice;
2, controllable problem Y-Δ, auto-coupling decompression start is simple, but only start. However, in the case of high degree of automation, it is estimated that it will be used less, or even softer. The regulation of the motor through the frequency converter, including the speed and voltage, is far from being comparable to the decompression start and soft start. Therefore, the inverter is the first choice for large or highly automated production lines. 3. Network communication The inverter itself can realize network monitoring through its integrated or extended communication port. Soft start can also do some monitoring, but real-time monitoring of the motor is also unmatched by decompression start and soft start. 4, maintenance aspects due to Y-Δ, auto-coupling decompression start itself is relatively simple, natural maintenance is also the simplest. I am actually against the use of soft start, if you do not choose the inverter, you will definitely choose Y-Δ or auto-decompression start. The inverter can complete the soft start and stop of the motor, so in the case of relatively large load, Y-Δ, auto-decompression start or soft start can not match the inverter.
