pehmeäkäynnistimet

Pehmeäkäynnistin is a Finnish term that translates to "soft starter" in English. It is an electronic device used to control the motor's starting torque and speed. Instead of applying full power to a motor instantly, a soft starter gradually increases the voltage supplied to the motor over a set period. This controlled ramp-up reduces the mechanical stress on the motor and connected equipment, such as pumps, fans, and conveyor belts.

The primary benefit of using a soft starter is the reduction of mechanical shock during startup. This leads to longer equipment lifespan and fewer maintenance requirements. Additionally, soft starters can prevent the large inrush current associated with direct-on-line (DOL) starting. This reduced current draw can lower energy consumption and prevent overloading of electrical distribution systems.

Soft starters typically employ silicon-controlled rectifiers (SCRs) or similar semiconductor devices to regulate the voltage. By controlling the firing angle of these devices, the output voltage to the motor can be precisely managed. Many soft starters also offer features like soft stopping, which similarly reduces the motor's speed gradually, preventing water hammer in pipe systems or jerking in conveyor belts. They are an alternative to variable frequency drives (VFDs) when speed control is not required, offering a more cost-effective solution for motor starting applications.