Abb Oy

Abb Beijing Drive Systems Co., Ltd.

Vesa Tiihonen

Pertti Seväkivi

Timo Väätäinen

Ari Hedemäki

A method in connection with a frequency converter and a frequency converter, the frequency converter being arranged for periodic recurrent use. The method comprises steps for generating and storing in a memory an average heating of a power semiconductor of the frequency converter, caused by one loading period, determining a temperature limit from the generated heating and the highest allowed temperature of the power semiconductor, determining the temperature of the power semiconductor in the frequency converter, and changing the operation mode of the frequency converter when the temperature of the power semiconductor exceeds the temperature limit when transferring to a loading period.

Method of changing an operation mode of a frequency converter based on temperature conditions, and a frequency converter having a changeable mode of operation based on temperature conditions

A load control apparatus adapted to indirectly detect an overcurrent, i.e. a current magnitude exceeding a predetermined limit value, occurring in an electric conductor element () belonging to a load current circuit (), on the basis of an increase in temperature. The load control apparatus () comprises a control current circuit including a temperature-sensitive switch member (S) capable of changing its operational state in response to an increase in the temperature to a predetermined value, and a control unit () adapted to detect a change in the operational state of the temperature-sensitive switch member (S), and to detect an overcurrent occurring in the electric conductor element () based thereon, the temperature-sensitive switch member (S) being adapted to be connected heat-conductively to a target element, in which at least part of the load current of the electric conductor element () passes in an operating situation, and the temperature-sensitive switch member (S) being further adapted to be electrically insulated from the electric conductor element () of the load current circuit.

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Vantaa, Finland

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