Ohjauskelan

Ohjauskelan, or control coil, is an electromagnetic winding used to actuate a mechanism within electrical or electromechanical devices. When energized with electrical current, the coil creates a magnetic field that moves a movable part, such as an armature or plunger, to close or open contacts, valve seats, or other actuators. The coil is typically designed to work with a magnetic circuit in a relay, contactor, solenoid valve, or similar device.

Construction and operation rely on a wound conductor, usually enamel-insulated copper or similar material, arranged around a magnetic core. The coil’s electrical properties—resistance, inductance, and overall impedance—determine the control current and the amount of magnetic force produced. Coils can be driven by direct current or alternating current, with designs often incorporating suppression components to minimize arcing and electrical noise. Cooling and insulation are important for reliability, especially in high-duty or compact applications.

Applications of ohjauskelat are widespread in automation and control systems. They are found in relays and contactors that switch higher power loads, in solenoid valves that control fluid or gas flow, and in various actuators and automatic equipment. Variants include latching (bistable) coils, which hold a position without continuous power, and high- or low-current coil designs tailored to specific control circuits.

Design considerations include coil resistance and heating, voltage and current ratings, duty cycle, and compatibility with the surrounding magnetic circuit. Compliance with insulation, safety, and electromagnetic compatibility standards is common in industrial applications. See also: solenoid, relay, actuator.