Patent ID: 7540355

Claim:
Elevator system, which elevator system is connected to an internal electricity distribution network of the building, which selectively connects between a public electricity distribution network and a reserve power appliance, and which elevator system comprises: at least one elevator; an elevator control system; an elevator motor; a frequency converter fitted to supply the elevator motor; an internal electricity distribution network to control the at least one elevator such that when the internal electricity distribution network of the building is connected to the reserve power appliance; wherein the elevator system can be used both when the internal electricity distribution network of the building is connected to the public electricity distribution network and when the internal electricity distribution network of the building is connected to a reserve power appliance and wherein the frequency converter will operate to manage the power supplied by the elevator system towards the internal electricity distribution network in direct relation to the demand capacity for electric power consumption of the internal electricity distribution network, such that total power supply towards the internal electricity distribution network does not exceed the power limit P a that can be set for the total power supply towards the internal electricity distribution network, and in order to avoid a rise in the voltage of the internal distribution network.