C & E. Fein Gmbh & Co.

C. & E. Fein Gmbh & Co. Kg

C&e Fein Gmbh

Christoph Meyer

Christoph Maier

Alfred Schreiber

Stefan Scherrenbacher

Christof Kress

Ralf Gosnik

Peter Wallitschka

A drilling device having a motor for driving a tool received in a tool holder, wherein the motor is coupled to a power source providing electrical operating power, and having a first switch for switching on the motor. A temperature switching element is provided, which is reversibly transferred from a first switching position to a second switching position, which shuts off the motor when the limit temperature of the switched-on motor is exceeded. For cooling the motor, the first switch and the temperature switching element are connected such that in the second switching position of the temperature switching element, it is possible to switch on the motor by pressing and holding the first switch. Moreover, the invention relates to a method for operating a drilling device.

Drilling device and method for operating a drilling device

A retarded electric motor designed as a series motor or an asynchronous motor having a squirrel cage rotor. A valve is provided for switching between motor operation and braking operation. During motor operation the motor is operated in a known configuration as series motor or as asynchronous motor. If configured as a series motor, the valve (S, S, S) allows to bypass the armature and to operate the motor as an externally excited direct current generator when switching into braking operation. If configured as an asynchronous motor, a switch is utilized to disconnect at least two field windings from mains. A valve is utilized to excite the motor externally from mains with a pulsating direct current during braking.

Electric motor with electronic brake

A series-wound motor is disclosed which is particularly suitable as a universal motor for an electric power tool. The motor comprises a stator with at least two field poles, each having two pole horns. At least one of the pole horns of each pole comprises first and second protrusions extending circumferentially from an axial edge of the pole horn. Sparking is reduced thereby. Also a retarded motor is disclosed, wherein each pole comprises a pole horn having a run-on edge, and further comprises a pole horn having a run-off edge. The pole horns having run-off edges are shortened in circumferential direction compared to the pole horns having run-on edges or comprise at least one cutout section extending in circumferential direction. The motor can be switched between a motor operation and a brake operation, without the need for providing commutating windings or additional coils to avoid excessive sparking.

Series-wound motor

A series motor with commutator is disclosed which is especially suited as universal motor for a braked power tool. The series motor comprises a switch for switching between a motor mode and a braking mode, wherein, in motor mode, at least one field winding is connected in series with an armature winding in a motor circuit, which is connected to an a.c. power source, and wherein, in braking mode, the at least one field winding and the armature winding form together a closed braking circuit disconnected from the power source. The secondary winding of a mains-operated transformer is connected within the braking circuit. This arrangement guarantees improved safety of the braking action.

Series motor

A series wound commutator motor is disclosed which is particularly suited for an inverse-speed electric tool. A switch is provided for switching between a motor operation mode and a braking operation mode, wherein in motor operation at least one field coil is connected in series with an armature winding in a motor circuit fed with a voltage supply and wherein in braking operation the at least one field coil with the armature winding forms a closed braking circuit separated from the voltage supply. A mains-supplied transformer is provided whose secondary winding is connected in the braking circuit parallel to the at least one field coil. A transistor circuit is provided for controlling the current flowing in the braking circuit through the armature winding and the at least one field coil.

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Stuttgart, Germany

Christoph Meyer