Vaihesäätö

Vaihesäätö, often translated as phase control, is a method used in electrical engineering to regulate the amount of power delivered to a load. It works by controlling the point in the alternating current (AC) waveform at which the current is allowed to flow. By selectively switching the current on and off during different parts of the AC cycle, the effective power delivered can be varied.

This technique typically involves the use of semiconductor switching devices such as silicon-controlled rectifiers (SCRs) or triacs. These devices can be triggered to conduct electricity at a specific phase angle of the AC voltage waveform. For example, in a heating application, delaying the turn-on point of the SCR will result in less current flowing through the heating element, thus reducing the heat output. Conversely, an earlier turn-on point allows more current to flow, increasing the heat.

Vaihesäätö is commonly employed in applications where smooth and continuous power adjustment is required. Examples include dimming incandescent lights, controlling the speed of universal motors in power tools and appliances, and regulating temperature in electric heaters. The primary advantage of vaihesäätö is its efficiency, as it does not dissipate significant amounts of power as heat, unlike rheostatic control methods. However, it can introduce harmonic distortion into the power supply, which may require filtering in sensitive applications.