Abstract: A method for starting an EC motor having a stator and a rotor, comprising the steps of determining a first position of the rotor when the rotor is stationary by means of discrete signal injection, accelerating the rotor by means of a controlled rotating field, determining a speed of the rotor on the basis of a back EMF after reaching a predetermined rotating field frequency, comparing the speed determined, with a first predetermined speed value, and, if the speed determined is greater than the first predetermined speed value, determining a second position of the rotor on the basis of the back EMF and changing to a closed-loop operation on the basis of the back EMF.

Abstract: A method for operating a permanently excited synchronous motor of a hand-held working device includes the steps of: sensorlessly determining a position variable representative of a position of a rotor of the synchronous motor at a standstill; determining a direction variable for a continuous rotation of the rotor from standstill in a direction on the basis of the determined position variable such that an absolute value of an attainable torque that can be generated by the synchronous motor during its sensorless actuation for the rotation in the direction is greater than an absolute value of a breakaway torque limit of the working device; and sensorlessly actuating the synchronous motor on the basis of the determined direction variable for the rotation in the direction.

Abstract: A method and a device are for operating a field-guided electric motor on a battery pack. In a motor mode, the motor current includes a field-forming motor current component and a torque-forming motor current component, which form a current amplitude of the motor current. In order to brake the electric motor fast with the option of possibly switching over to accelerating the electric motor at any time, provision is made for dividing the braking mode into two temporally separate braking sections. In a first braking section, the current amplitude of the motor current is kept constant by adjusting the field-forming motor current component. In a second braking section, the current amplitude of the motor current is variable. The switching of the braking mode over from the first braking section to the second braking section takes place when there is a fall below a predetermined speed of the electric motor.

Abstract: A method operates an electrically driven working device with at least one battery pack that is intended to supply the working device with electric drive power, wherein the working device and the battery pack are electrically connected to one another in detachable fashion for power supply purposes. The working device is selected from a set of different working devices able to be electrically connected to the battery pack in detachable fashion, which working devices differ in terms of a respective power consumption variable, and/or the working device has different operating modes that differ in terms of a respective power consumption variable. At least one power consumption variable, in particular during operation of the working device with the battery pack, is at least temporarily higher than a continuous power output variable of the battery pack.

Abstract: A method for ascertaining, without an encoder, a rotational angle position of the rotor of a brushless DC motor, includes the steps of: detecting a voltage induced in a stator of the brushless DC motor; checking whether the voltage induced in the stator is lower than a threshold value; and if the induced voltage is lower than the threshold value, then ascertaining an initial rotational angle position of the rotor based on an Indirect Flux detection by Online Reactance Measurement, and subsequently updating the rotational angle position proceeding from the calculated initial rotational angle position using at least one continuous test signal.

Abstract: A method for operating a permanently excited synchronous motor of a hand-held working device includes the steps of: sensorlessly determining a position variable representative of a position of a rotor of the synchronous motor at a standstill; determining a direction variable for a continuous rotation of the rotor from standstill in a direction on the basis of the determined position variable such that an absolute value of an attainable torque that can be generated by the synchronous motor during its sensorless actuation for the rotation in the direction is greater than an absolute value of a breakaway torque limit of the working device; and sensorlessly actuating the synchronous motor on the basis of the determined direction variable for the rotation in the direction.

Abstract: A method for ascertaining, without an encoder, a rotational angle position of the rotor of a brushless DC motor, includes the steps of: detecting a voltage induced in a stator of the brushless DC motor; checking whether the voltage induced in the stator is lower than a threshold value; and if the induced voltage is lower than the threshold value, then ascertaining an initial rotational angle position of the rotor based on an Indirect Flux detection by Online Reactance Measurement, and subsequently updating the rotational angle position proceeding from the calculated initial rotational angle position using at least one continuous test signal.

Abstract: A ceramic component is formed of at least one stack of two or more layers of one-directional non-woven carbon fiber fabrics embedded in a ceramic matrix containing silicon carbide and elemental silicon. All adjacent layers within the at least one stack directly adjoin each other. The at least one stack has a minimum thickness of 1.5 mm perpendicularly to the plane of the layers. The ceramic matrix permeates substantially the entire component.

Abstract: The present invention provides a method and a device to determine the rotor field angle of an asynchronous machine even during the magnetising phase, in which the rotor field of a rotor of the asynchronous machine is built up. The asynchronous machine can then be actuated in a controlled operating mode even during the magnetising phase. The startup properties of the asynchronous machine can thus be improved, the magnetising phase of the asynchronous machine is shortened and it is possible to set a desired torque even during the magnetising phase.

Abstract: The invention relates to a welding robot for resistance welding, which exhibits a welding tongs (21), a welding current generator (1) connected to the welding electrodes (24, 25) of the welding tongs (21), for supplying the welding electrodes (24, 25) with electric energy during the resistance welding, and an industrial robot. The industrial robot comprises a robot arm (2) and a robot control device (9) for moving the robot arm (2). The welding tongs (21) is connected to the robot arm (2) and the robot control device (9) is connected to the welding current generator (1) and a tongs drive (26, 27) of the welding tongs (21).

Abstract: A method for determining state variables of an electric motor for driving a motor vehicle, comprising the procedural steps: measuring (102, 104) data (103, 105) which comprise information about a current state of vehicle components (10, 12, 30, 40); converting (110) the measured data (103, 105) into data (111) related to the electric motor (10) using a vehicle model of the motor vehicle (1); evaluating (120) the data (111) related to the electric motor (10) using a machine model of the electric motor (10) for determining at least one first state variable (121) of the electric motor (10); determining (130) at least one second state variable (131) of the electric motor (10) using a sensorless method; comparing and assessing for plausibility (140) the at least one first and the at least one second state variable (121, 131).

Abstract: A method for determining state variables of an electric motor for driving a motor vehicle, comprising the procedural steps: measuring (102, 104) data (103, 105) which comprise information about a current state of vehicle components (10, 12, 30, 40); converting (110) the measured data (103, 105) into data (111) related to the electric motor (10) using a vehicle model of the motor vehicle (1); evaluating (120) the data (111) related to the electric motor (10) using a machine model of the electric motor (10) for determining at least one first state variable (121) of the electric motor (10); determining (130) at least one second state variable (131) of the electric motor (10) using a sensorless method; comparing and assessing for plausibility (140) the at least one first and the at least one second state variable (121, 131).