Abstract: A circuit for activating an electric motor in a work apparatus includes a main circuit having an electric motor, a rechargeable-battery pack, and an operating switch for activating the motor, and also a parallel branch to the battery pack and the operating switch. A capacitor is arranged in the parallel branch. To lower the electrical contact load on the operating switch, provision is made to arrange an electronic switch, which is connected in series with the capacitor, in the parallel branch. The series circuit which includes the capacitor and the electronic switch has a first and a second end. The ends form the only electrical power connection of the capacitor to the main circuit. The electronic switch in the series circuit will apply a supply voltage, which is provided by the battery pack, to the capacitor only after a period of time following closing of the operating switch has elapsed.

Abstract: The invention is directed to a method for braking an electric drive motor having a stator and a rotor. The stator has field coils which have electrical phase connections for three motor phases. To generate an electromagnetic rotating field driving the rotor, the phase connections are connected to a supply voltage via switches actuated by a control unit which closes the switches depending on the rotary position of the rotor. To brake a rotating rotor, a braking current is generated by short-circuiting the phase connections. A phase short circuit is switched in between each two phase connections of the field coils with a preset temporal sequence to brake the rotor. The phase connections short-circuited are each selected corresponding to the rotary position of the rotor so that that field coil is short circuited in which the voltage induced by the magnetic field of the rotating rotor passes through its maximum.

Abstract: A capacitor power supply unit converts a mains voltage (U) into a lower operating voltage (V1) for a controller and a supply voltage (V2) for an electrical small load. A series circuit including a mains capacitor and a zener diode is connected to the mains voltage (U) whereat the supply voltage (V2) for an electrical small load having a permissible operating voltage is tapped off. The capacitor power supply unit provides for the supply voltage (V2) to be greater than the permissible operating voltage of the electrical small load and for the small load to be connected to the supply voltage (V2) via a buck converter. Here, the buck converter is controlled as a current source having a variable operating frequency.

Abstract: A handheld work apparatus has an electric drive motor (24) and a power supply unit for the drive motor (24). The power supply unit is arranged in a receptacle (7) of a housing (2) of the work apparatus. The work apparatus has an electronic control (17) and a blower wheel (29) for conveying cooling air. The blower wheel (29) is driven by a drive motor (24). The housing (2) has at least one air inlet opening (10) for cooling air via which the blower wheel (29) draws in a first cooling air flow (22) during operation. A second cooling air flow (23) is drawn into the housing (2) via the receptacle (7).

Abstract: The invention is directed to a protective circuit for a multiplicity of individual cells arranged in a rechargeable battery pack, wherein a predefined number of individual cells forms a cell network. A monitoring circuit for the state of charge of the individual cells in the cell network is provided wherein the voltage at an individual cell is detected and the detected voltages of a plurality of individual cells are compared among one another to output a signal when an unbalancing limit is exceeded unbalancing limit indicates a permissible voltage difference between two selected individual cells of the cell network. The unbalancing limit of the cell network is provided as a characteristic curve variable over its state of charge. To alter the unbalancing limit, the characteristic curve is altered in dependence on a correction value.

Abstract: The invention is directed to a method for braking an electric drive motor having a stator and a rotor. The stator has field coils which have electrical phase connections for three motor phases. To generate an electromagnetic rotating field driving the rotor, the phase connections are connected to a supply voltage via switches actuated by a control unit which closes the switches depending on the rotary position of the rotor. To brake a rotating rotor, a braking current is generated by short-circuiting the phase connections. A phase short circuit is switched in between each two phase connections of the field coils with a preset temporal sequence to brake the rotor. The phase connections short-circuited are each selected corresponding to the rotary position of the rotor so that that field coil is short circuited in which the voltage induced by the magnetic field of the rotating rotor passes through its maximum.

Abstract: The invention is directed to a rechargeable battery pack for an electrical load with the load being connected to the rechargeable battery pack by a connection cable. A housing of the rechargeable battery pack has an inner space for accommodating a large number of rechargeable individual cells which are electrically connected to one another and supply the load via the connection cable. To provide the housing with a high level of stability, provision is made for the receiving space in the housing to be subdivided into individual receptacles by partition walls. A cell pack includes a predefined number of the individual cells and is arranged in a corresponding individual receptacle. Each cell pack forms an independent unit which is held in the individual receptacle. The individual cells of a cell pack are electrically and mechanically connected to one another by cell connectors.

Abstract: An electric motor includes an arrangement of windings provided for driving the rotor, with the windings being connected to an energy source to develop torque which drives the rotor. The electric circuits of corresponding ones of the windings each have a potential point, the voltage (UL, UG) of which is supplied to an evaluation unit via an adaptation device. The adaptation device can be operated in two switchable adaptation stages and is connected to a drive circuit that operates in dependence upon the rotational position of the rotor. The drive circuit switches the adaptation device into the first stage having a high sensitivity or into the second stage having a low sensitivity in dependence upon the rotational position of the rotor of the motor, such that the number of required analog inputs at a microprocessor in the evaluation unit can be kept low.

Abstract: A protective circuit for an arrangement includes a multiplicity of individual cells in a rechargeable battery pack. A predefined number of individual cells are connected in series in a cell row and at least two cell rows are mutually parallel, and at least one cell connector situated between the individual cells at a location of one cell row is electrically connected via a compensation line to the cell connector situated at an identical location of the parallel cell row, and the potential of the cell connector connected to the compensation line at one location of one cell row and the potential of the cell connector electrically connected to the compensation line at the same location of the parallel cell row are detected and the detected potentials are fed to an evaluation unit.

Abstract: The invention relates to a method for starting an electronic drive circuit for the windings of an electric motor. A control unit, which is connected to a voltage source, is provided as well as a capacitor connected via a system switch element to the connecting terminals of the voltage source. The capacitor is connected across the input terminals parallel to the drive circuit. An operating circuit controls the system switch element. In order to start the motor, the operating circuit closes the system switch element and charges the capacitor and after the charging of the capacitor, opens the system switch element again. A test step is then started by the control unit, the drive circuit being supplied exclusively by the capacitor voltage (UC) during the test step.

Abstract: An electric power tool has a drive motor and an electronic control unit. Power is supplied by a battery pack with several individual cells and a monitoring circuit for the operating parameters of the cells. A communication line connects electronic control unit and monitoring circuit. Digital data are exchanged through the communication line between electronic control unit and monitoring circuit. A controller controls data traffic through sending and receiving units. The communication voltage is higher than a permissible input voltage level of the controller and lower than a maximum battery pack voltage. The receiving unit, as a filter, converts a received first signal level that is lower than a first voltage to a LOW signal and lowers a received second signal level that is higher than a second voltage to the input voltage level of the controller and relays the second signal level as a HIGH signal.

Abstract: An electric chain saw has an electric drive motor defining a motor-specific characteristic line of the drawn-in current as a function of the rotational speed of the motor. A control unit controls the current flowing through the drive motor below an engaging rotational speed to values below the motor-specific characteristic line. In order to generate an operating point the operator can feel in a working region in a predetermined rotational speed band, a control characteristic line of the electric input power of the electric drive motor as a function of the rotational speed is provided above the engaging rotational speed. The control characteristic line is adapted to reduce the electric input power within the rotational speed band to an approximately even mean power so as to cause the torque of the drive motor to increase within the rotational speed band with falling rotational speed.

Abstract: A circuit for activating an electric motor in a work apparatus includes a main circuit having an electric motor, a rechargeable-battery pack, and an operating switch for activating the motor, and also a parallel branch to the battery pack and the operating switch. A capacitor is arranged in the parallel branch. To lower the electrical contact load on the operating switch, provision is made to arrange an electronic switch, which is connected in series with the capacitor, in the parallel branch. The series circuit which includes the capacitor and the electronic switch has a first and a second end. The ends form the only electrical power connection of the capacitor to the main circuit. The electronic switch in the series circuit will apply a supply voltage, which is provided by the battery pack, to the capacitor only after a period of time following closing of the operating switch has elapsed.

Abstract: A hand-held power tool has a tool member and a motor drivingly connected to the tool member, wherein the motor is arranged in a motor housing. A battery for driving the tool member is provided. A guide shaft has arranged on its first end the battery and on its second end the motor housing and the tool member. A rotatably power output part arranged on the motor housing is drivingly connected to the motor. The power output part supports the tool member. Cooling air is sucked through the guide shaft into the motor housing. Between the power output part and the motor housing an annular air exit gap is formed through which the cooling air exits the motor housing. At least one guide vane that projects into the annular air exit gap is provided.

Abstract: A hand-held power tool has a device housing and at least one grip disposed on the device housing. An electric drive motor is arranged in the device housing for operating a working tool. A battery pack provides electric energy for operating the electric drive motor. An electronic control unit is connected to the electric drive motor and the battery pack. An operating element disposed on the grip controls the electric drive motor. An electric actuator is acted upon by the operating element and the output signal of the electric actuator is supplied to the electronic control unit. Electric energy is applied to the electric drive motor by the electronic control unit as a function of a position of the operating element, wherein in a first dead travel range of the operating element that adjoins an inoperative position of the operating element the supplied electric energy is zero.

Abstract: An electric motor includes an arrangement of windings provided for driving the rotor, with the windings being connected to an energy source to develop torque which drives the rotor. The electric circuits of corresponding ones of the a windings each have a potential point, the voltage (UL, UG) of which is supplied to an evaluation unit via an adaptation device. The adaptation device can be operated in two switchable adaptation stages and is connected to a drive circuit that operates in dependence upon the rotational position of the rotor. The drive circuit switches the adaptation device into the first stage having a high sensitivity or into the second stage having a low sensitivity in dependence upon the rotational position of the rotor of the motor, such that the number of required analog inputs at a microprocessor in the evaluation unit can be kept low.

Abstract: The invention relates to a method for starting an electronic drive circuit for the windings of an electric motor. A control unit, which is connected to a voltage source, is provided as well as a capacitor connected via a system switch element to the connecting terminals of the voltage source. The capacitor is connected across the input terminals parallel to the drive circuit. An operating circuit controls the system switch element. In order to start the motor, the operating circuit closes the system switch element and charges the capacitor and after the charging of the capacitor, opens the system switch element again. A test step is then started by the control unit, the drive circuit being supplied exclusively by the capacitor voltage (UC) during the test step.

Abstract: An electric chain saw has an electric drive motor defining a motor-specific characteristic line of the drawn-in current as a function of the rotational speed of the motor. A control unit controls the current flowing through the drive motor below an engaging rotational speed to values below the motor-specific characteristic line. In order to generate an operating point the operator can feel in a working region in a predetermined rotational speed band, a control characteristic line of the electric input power of the electric drive motor as a function of the rotational speed is provided above the engaging rotational speed. The control characteristic line is adapted to reduce the electric input power within the rotational speed band to an approximately even mean power so as to cause the torque of the drive motor to increase within the rotational speed band with falling rotational speed.

Abstract: A handheld work apparatus has an electric drive motor (24) and a power supply unit for the drive motor (24). The power supply unit is arranged in a receptacle (7) of a housing (2) of the work apparatus. The work apparatus has an electronic control (17) and a blower wheel (29) for conveying cooling air. The blower wheel (29) is driven by a drive motor (24). The housing (2) has at least one air inlet opening (10) for cooling air via which the blower wheel (29) draws in a first cooling air flow (22) during operation. A second cooling air flow (23) is drawn into the housing (2) via the receptacle (7).

Abstract: A hand-held power tool has a tool member and a motor drivingly connected to the tool member, wherein the motor is arranged in a motor housing. A battery for driving the tool member is provided. A guide shaft has arranged on its first end the battery and on its second end the motor housing and the tool member. A rotatably power output part arranged on the motor housing is drivingly connected to the motor. The power output part supports the tool member. Cooling air is sucked through the guide shaft into the motor housing. Between the power output part and the motor housing an annular air exit gap is formed through which the cooling air exits the motor housing. At least one guide vane that projects into the annular air exit gap is provided.