Robert Boschgmbh

Audi Ag

C & E. Fein Gmbh & Co.

Metabowerke Gmbh & Co.

Hans Hermann Rottmerhusen

Boris E Rudolf

An electrodynamic braking device for a universal motor includes a field winding configured to be fed from a grid during a braking operation, and an armature that is configured to be directly short-circuited. A braking process is performed by means of control electronics. Good braking is achieved with relatively low brush wear. Such an electrodynamic braking device can be used effectively for a power tool.

Braking device for a universal motor

A method for operating a mains-operated electric motor for a power tool includes connecting a first side of an electric motor to a first mains and connecting a second side of the electric motor to a second mains using first and second switches, respectively, in particular semiconductor switches, and monitoring the operational reliability of the switches using an electronic controller for operating safety.

Disconnection from mains using switches for power tools

An electrodynamic braking device for a universal motor is proposed, wherein during a braking operation a field winding is supplied from a network, and an armature is directly short-circuited, and a braking operation is carried out using a program of a controller of a control electronics system, whereby good braking is achieved with relatively low brush wear. Such an electrodynamic braking device is advantageously applied in a power tool equipped with a dangerous tool.

Electrodynamic braking device for a universal motor

The invention relates to an electrodynamic braking device and to a method for braking a universal motor having a field winding and an armature. The universal motor can be switched from a motor mode to a braking mode. In the motor mode, the armature and the field winding are supplied with an alternating current of a power grid. In the braking mode, the armature is short-circuited and the field winding continues to be supplied with an alternating current from the power grid. In a first phase of the braking mode, the field winding can be supplied with an alternating current having the frequency of the power grid. In a further phase of the braking mode, the field winding is supplied by the power grid with an alternating current having a frequency that is reduced with respect to the frequency of the power grid.

Disclosed is an electromotive power steering for a motor vehicle, in which a special type of reluctance motor or series wound motor is used while such an electric motor is electronically commutated. In order to recognize an error condition in the electronic control device and the electric motor, adequate mechanisms are provided in the circuit arrangement (), the electric motor being cut from the power source by means of a relay () or by short-circuiting the power source downstream of a safety device () with the aid of a thyristor ().

Electromotive power steering

Disclosed is an electric drive for a vehicle, which is used as a main drive or a hybrid drive. The electric motor of said drive is embodied as a special type of reluctance motor or series wound motor. The rotor of the reluctance motor and the inverse speed motor is provided with an excitation winding to which a transistor is assigned that allows the motor to be braked in a sensitive manner so as to control the field current. The braking current is fed to the source of current by switching operation of the motor during generator operation.

Electric drive for a vehicle

The invention relates to a control system for a commutator motor which is operated by phase-fired control. Allocation of a first and second control device in a single operating state without transition makes it possible to obtain constant jolting rotation of said motor by continuously varied cutting of the half-waves into first and second area sections ( ) of an alternative current voltage. The inventive type of control system can be used advantageously in electric screwing or drilling tools.

Commutator motor control system

A portable power tool has, in order to drive a tool (12), a hollow spindle (14) to which the tool (12) can be fastened between two flanges (16, 18). The outer flange (16) is configured at the end of a clamping bolt (22) that is inserted through a central opening (17) of the tool (12) and projects at its other end out of the housing (42). The clamping bolt (22) can be non-rotatably secured at this end by means of a retaining element (20). For actuation, a clamping device (24) is provided, which can be moved, against the force of spring elements (26), between a clamped position in which the retaining element (20) is acted upon axially to clamp the tool (12), and a released position in which the tool is disengaged for manual changing. The spring elements (26) are arranged between an axial fixed stop (28) and an axially displaceable stop (FIG. 1).

Growing community of inventors

Tellingstedt, Germany

Hans Hermann Rottmerhusen