Vaiheensäätimet

Vaiheensäätimet, often translated as phase controllers or phase angle controllers, are electronic devices used to control the power delivered to a load by regulating the phase angle of the alternating current (AC) waveform. They operate by switching the AC power on and off during each half-cycle of the waveform. By controlling the point in the cycle at which the switching occurs, the amount of power delivered to the load can be precisely adjusted. This is typically achieved using semiconductor devices such as thyristors (SCRs) or triacs.

The primary function of a vaiheensäädin is to vary the RMS voltage supplied to a load, thereby controlling its power output. This makes them suitable for applications requiring variable power, such as dimming lights, controlling motor speed, regulating heater temperature, and managing power in welding equipment. The control mechanism can be manual, through a potentiometer, or automatic, responding to feedback signals from sensors.

Compared to simple on-off control (like a thermostat), vaiheensäätimet offer smoother and more precise control over the power delivered, leading to less mechanical stress and more efficient operation in many systems. However, they can introduce harmonic distortion into the power supply, which may require filtering in some sensitive applications. The choice of semiconductor device depends on the voltage and current requirements of the load, as well as the desired level of control and efficiency.