Käynnistysapukäämi

Käynnistysapukäämi, often translated as starting assistance coil or sometimes a starting booster coil, is a component found in some electrical systems, particularly in older or simpler designs of appliances and machinery. Its primary function is to provide an initial surge of torque or power to help a motor start rotating. This is especially useful for motors that have difficulty overcoming their initial inertia or the load they are intended to drive from a standstill.

The käynnistysapukäämi operates by creating a temporary magnetic field that is out of phase with the main motor winding. This phase difference generates a rotating magnetic field, which then induces a current in the motor's rotor. This induced current interacts with the stator's magnetic field, producing the necessary starting torque. Once the motor reaches a certain speed, typically around 70-80% of its rated speed, a centrifugal switch or other timing mechanism disengages the käynnistysapukäämi. This prevents it from consuming unnecessary power and potentially overheating, as it is not designed for continuous operation.

The presence and design of a käynnistysapukäämi can significantly impact a motor's starting characteristics, allowing it to start under heavier loads or in colder conditions where resistance is higher. While more sophisticated starting methods are common in modern, high-power motors, the käynnistysapukäämi remains a viable and cost-effective solution for many smaller and medium-sized applications.