käynnistyskondensaattori

Käynnistyskondensaattori is a Finnish term referring to a starting capacitor used in electric motors. Its primary function is to provide a temporary boost in torque to help single-phase AC motors start rotating. Many common single-phase motors, such as those found in appliances like refrigerators, washing machines, and fans, require a starting capacitor to overcome their initial inertia and begin turning.

The käynnistyskondensaattori is typically connected in series with an auxiliary winding in the motor. When the motor is energized, the capacitor creates a phase shift in the current supplied to the auxiliary winding, generating a rotating magnetic field. This field is essential for initiating the motor's rotation. Once the motor reaches a certain speed, usually around 75% of its full operating speed, a centrifugal switch or a current-sensitive relay disconnects the käynnistyskondensaattori from the circuit. This is because the capacitor is not designed for continuous operation and would overheat or fail if left connected.

The capacitance value of a käynnistyskondensaattori is crucial for proper motor starting. Too small a capacitance may not provide sufficient torque, while too large a capacitance can lead to excessive starting current and potential damage to the motor. Starting capacitors are generally electrolytic capacitors, designed for intermittent duty. They are distinct from run capacitors, which are designed for continuous operation and are used to improve motor efficiency and power factor. Identifying and replacing a faulty käynnistyskondensaattori is a common repair for motors that fail to start or exhibit weak starting performance.