Open Circuit Losses

Open-circuit losses in electrical components occur when power is supplied to the machine or the component without useful power being produced. In electrical engineering, for example, electric motors, transformers or power supplies can be affected by open-circuit losses. In the case of transformers, the open circuit losses result from the nominal voltage without load. In addition, the copper losses are another decisive aspect that must be taken into account in the open circuit losses. These result from the ohmic resistance of the winding. In large transformers, such as power transformers, the open-circuit losses are due to the iron losses in the core. In electric motors, on the other hand, there are two components that influence the open-circuit losses. Firstly, the iron losses in the core, just as with transformers. On the other hand, the friction in the bearings of the motor, which are also loaded when the motor is idling, without the motor being under load.