Kondensaattorikäynnistystä

Kondensaattorikäynnistystä is a Finnish term referring to capacitor-start starting for electric motors. This method is employed to provide the necessary torque to start single-phase induction motors, which would otherwise have difficulty starting under load.

The principle of capacitor-start involves using a capacitor in conjunction with a starting winding. When the motor is energized, the capacitor is placed in series with the starting winding. This creates a phase shift between the current in the starting winding and the current in the main running winding. The resulting magnetic field from these two windings, being out of phase, produces a rotating magnetic field, which is essential for initiating motor rotation.

The capacitor is typically a high-value electrolytic capacitor chosen to provide a significant boost in starting torque. Once the motor reaches a certain speed, usually around 75-80% of its rated speed, a centrifugal switch or a time-delay relay disconnects the starting winding and the capacitor from the circuit. The motor then continues to run solely on its main winding.

Capacitor-start motors are commonly used in applications requiring high starting torque, such as compressors, pumps, and some power tools. They offer a cost-effective solution for increasing the starting performance of single-phase motors compared to other methods like capacitor-run or split-phase designs. The capacitor's role is solely for starting, making it an efficient and temporary addition to the motor circuit.