käynnistysrasitusta

Käynnistysrasitus, often translated as starting load or inrush current, refers to the temporary but significantly higher electrical current that a device or motor draws when it is first powered on. This phenomenon is particularly pronounced in devices with inductive components, such as electric motors, transformers, and fluorescent lamps.

When an inductive load is switched on, its magnetic field is initially absent and must build up from zero. This process requires a large amount of energy, which is drawn from the power source as a surge of current. This current can be several times the normal operating current and typically lasts for a very short duration, usually a few milliseconds to a few seconds.

The magnitude of the käynnistysrasitus depends on factors like the type of device, its design, and the moment in the AC power cycle when it is switched on. For motors, the rotor's initial state of rest and the magnetic field's build-up are key contributors.

High starting loads can have several implications. They can cause voltage dips in the electrical supply, potentially affecting other connected equipment. They can also place stress on power system components, such as fuses, circuit breakers, and wiring, necessitating appropriately sized protection devices. In some industrial applications, strategies like soft starters or variable frequency drives are employed to gradually ramp up the power to motors, thereby reducing the käynnistysrasitus and its associated stresses. Understanding and managing käynnistysrasitus is crucial for reliable and efficient electrical system design and operation.