Method for closing a contactor, and contactor having temperature compensation

A method for closing contacts of an electrical switching device during a switch-on process, wherein the electrical switching device comprises an electromechanical drive with a coil and an armature which can be moved between an open and a closed position, and a microcontroller electrically coupled to the electrical switching device, the method comprising:

• energizing the coil in order to close the contacts of the electrical switching device;
• applying first a first voltage U1 to the coil during a first time period T1, wherein the first voltage U1 is constant;
• determining a measurement value;
• determining, based on the measurement value, a second voltage U2 from a table stored in a memory of the microcontroller, the table defining a correlation between the measurement value and the second voltage U2, wherein the second voltage U2 is greater than the first voltage U1, the second voltage U2 being constant;
• and
• applying the second voltage U2 to the coil during a second time period T2 in order to move the armature from the open position into the closed position, wherein the second time period T2 directly follows the first time period T1, and
• wherein
• either the first time period T1 is fixed, and the measurement value is a current measurement value IMess determined at the end of the first time period T1 by measuring the current flowing in the coil, the first time period T1 and the first voltage U1 being selected in such a way that the armature is not set into motion during the first time period T1,
• or the first voltage U1 is applied to the coil until a certain current value ISoll of the current flowing in the coil is reached, the first time period T1 being the time period until said certain current value ISoll is reached, the first time period T1 being the measurement value, and the first voltage U1 being selected in such a way that the armature is not set into motion during the first time period T1,
• wherein the first time period T1 is selected in such a way that the current increases during the total first time period T1 and no stationary final current appears in the coil during the first time period T1.