Soft starters offer multiple functions, including soft start, soft stop, pump control, and timed low-speed operation, giving them unparalleled advantages over traditional step-down starters in power equipment control for industrial and civil buildings.
Below is an introduction to the circuit applications of soft starters and their suitable operating current requirements.
In principle, soft starters are suitable for various applications that do not require speed regulation. Current application ranges include AC 380V (660V is also possible), with motor power ranging from several kilowatts to 800kW. Soft starters are particularly suitable for various pump or fan loads requiring soft start and soft stop. Similarly, for variable load conditions, where the motor operates under light load for extended periods and only briefly or momentarily under heavy load, using a soft starter (without a bypass contactor) provides energy savings under light load conditions.
- Rectifier: It connects to a single-phase or three-phase AC power supply to generate a pulsating DC voltage.
- The intermediate circuit has the following three functions:
(1) To stabilize or smooth the pulsating DC voltage for use by the inverter.
(2) To supply power to various control circuits via a switching power supply.
(3) To be equipped with filtering or braking devices to improve the performance of the soft starter.
- The inverter converts fixed DC power into AC voltage with variable voltage and frequency.