Landis & Gyr Technology Innovation Ag

Krister Larsson

The invention concerns a method and an apparatus for actuating a plurality of synchronous motors which are connected to a common power supply and which are respectively used for displacing an element between two limit positions and have a connection Y1 for forward motion, a connection Y2 for reverse motion and a neutral connection G. In that case the respective connection between the connection Y1 or Y2 which is in use and the power supply is interrupted by means of a limit switch which responds when the element reaches a limit position. The connection between the connection Y2 or Y1 which is not in use and the power supply remains interrupted during non-use. A respective switch element having a control input is connected upstream of the connection Y1 for forward motion and the connection for reverse motion. The control input of the switch element is connected to a respective control circuit which includes the respective limit switch. The advantages of the invention are that electromagnetic actuating members with a synchronous motor of that kind can be connected in parallel by way of limit switches without malfunctions occurring when the limit switches respond. The amount of wear of the synchronous motors is reduced and the service life thereof is thereby increased. The level of power consumption is reduced and the amount of noise developed is decreased.

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Huddinge, Sweden

Krister Larsson