tilkoblingsstrøm

Tilkoblingsstrøm, also known as inrush current, is the instantaneous, high electrical current drawn by certain electrical devices when they are first connected to a power source. This phenomenon is most commonly observed in devices with inductive loads, such as electric motors, transformers, and fluorescent lamps. When these devices are powered on, the magnetic fields within them are initially zero and must build up to their operational levels. This process requires a significant amount of energy to be drawn from the power supply in a very short period, resulting in a current surge that can be many times the device's normal operating current.

The magnitude and duration of the tilkoblingsstrøm depend on several factors, including the device's design, its operating voltage, and the point in the AC voltage cycle at which it is switched on. For motors, the inrush current can be as high as six to eight times their rated full-load current and can last for a few seconds. This temporary surge can cause problems such as tripping circuit breakers or fuses, overloading power supplies, and causing voltage dips in the electrical network.

To mitigate the effects of tilkoblingsstrøm, various techniques are employed. Soft starters and variable frequency drives (VFDs) are commonly used with electric motors to gradually ramp up the voltage and current, thereby reducing the inrush. For transformers, the magnetic flux built up during manufacturing and the point of switching also influence the inrush current. Understanding and managing tilkoblingsstrøm is crucial for the reliable operation and longevity of electrical equipment and systems.