Abstract: A pressing tool includes a motor, a sensor, and a microcontroller coupled to the motor and the sensor. The microcontroller is configured to cause the motor to operate in a first direction, and obtain a motor parameter from the sensor. The microcontroller is further configured to determine an occurrence of a fault condition of the motor when the motor parameter satisfies a threshold. In response to determining the fault condition, the microcontroller is further configured to cause the motor to change from operation in the first direction to operate in a second direction, pause operation of the motor in the second direction, and resume operation of the motor in the first direction.

Abstract: A heat pump device includes an inverter control unit outputting PWM signals to an inverter; a current detection unit detecting a current value flowing in the inverter and outputting the current value after reducing a current value having a first frequency or higher in detected current value; and a drive-signal stop unit that, when the current value output from the current detection unit is equal to or larger than an interruption level, stops output of PWM signals to the inverter. Particularly, the inverter control unit generates a voltage command value such that the voltage command value becomes a value equal to or larger than a lower limit determined according to the first frequency and generates PWM signals based on generated voltage command value and a carrier signal, thereby causing a voltage output time to the motor to be a predetermined time or longer.

Abstract: Controlling an output of a mining system. The control includes receiving, at a processor, a first signal associated with a position of the shearer, determining, using the processor, the position of the shearer based on the first signal, receiving, at the processor, a second signal associated with a load of a conveyor, and determining, using the processor, the load of the conveyor based on the second signal. The method further includes determining, using the processor, an output of the mining system based on the position of the shearer and the load of the conveyor and controlling a speed of the shearer based on the output of the mining system.

Abstract: The invention relates to a linear actuator (5) including drive means (10) for driving a movable component assembly (15) for actuating a tool (20), controlled by an electronic module (25), characterised in that the module (25) comprises acquisition means for acquiring a quantity that is representative of the instantaneous force supplied by the drive means (10) and/or the time derivative of this variable, and in that the electronic module (25) is capable of controlling interruption means for interrupting the operation of the drive means (10) if the said variable does not exceed a first predetermined value during a first predetermined time period from the start of the driving of the movable component assembly (15), and/or if the said derivative does not exceed a second predetermined value during the first predetermined time period from the start of the driving of the movable component assembly (15).

Abstract: An electric power tool includes a voltage step-up condition setting operation unit that serves as a human machine interface and a voltage converter capable of performing a voltage step-up operation to raise a voltage supplied from a power supply and supply a raised voltage to a motor. The voltage converter is further capable of changing a voltage step-up level in the voltage step-up operation in accordance with the operation of the voltage step-up condition setting operation unit. A driving state detection unit generates a driving state signal corresponding to a driving state of the electric power tool. A control unit controls a stop timing of the motor in accordance with the driving state signal.

Abstract: A power tool includes a brushless DC motor housed inside a tool housing, an input unit, and a control unit. The motor includes a rotor, a stator, and at least one sensor positioned to sense a state of the rotational position of the rotor inside the stator. A control unit controls commutation of the motor through a series of power switches coupled to the power supply. The control unit receives a current sensor state from the sensor and a user-selected speed from the input unit and determines whether the motor has reversed direction using the user-selected speed and the current sensor state. The control unit disables commutation of the motor if the motor has reversed direction until a proper current sensor state is received from the sensor.

Abstract: A power tool includes a housing, a brushless DC motor housed inside the housing, a power supply, a control unit, and an input unit such as a trigger switch actuated by a user. The control unit controls the commutation of the motor through a series of power switches coupled to the power supply. The control unit initiates electronic braking of the motor after occurrence of a condition in the input unit, such as trigger release or reduced speed, indicative of the power tool shut-down. A mechanism is provided to power the control unit for a predetermined amount of time after the detection of the condition from the input unit in order to complete the electronic braking of the motor.

Abstract: A drilling device prevents recurrence of an overload condition after occurrence of the overload condition, thereby improving operability and safety in the drilling device. A motor for rotating a drill is connected to an AC power source through a motor control unit, a current detector, and a power switch. A magnet is also connected to the AC power source through the power switch and a full-wave rectifier. The motor control unit rotationally drives the motor on the basis of a signal sent from a main control unit according to a state in which a motor start switch is on. The main control unit controls the motor control unit to gradually reduce a supply voltage to the motor when the motor becomes overloaded, to gradually increase the voltage to the normal power supply condition when the overload condition is vanished, and to stop power supply to the motor if the overload condition continues for a predetermined period.

Abstract: A circuit for a series motor for a power tool is disclosed, wherein reliable switching is achieved by means of two electronic switches, without the use of a mechanically disconnecting switch. To this end, two electronic switches, preferably triacs, are preferably connected in series to each other, the voltage drop across the triacs being continuously monitored by a monitoring circuit. A check for faults can be carried out before switching on the power tool. Alternatively, a fusible cutout can be tripped by means of a protective switch connected in parallel thereto.

Abstract: The invention relates to a method and an arrangement for adjusting the percussion and the feed of a rock drilling apparatus with respect to each other. In the method, the volume flow of pressure fluid to be supplied to a percussion device (7) and a feed motor (8) is adjusted on the basis of the feed pressure of the feed motor (11), a volume flow adjusted pump (1) being controlled so that the ratio of the pressure applied to the persussion device (7) to the pressure of the feed motor (11) is set by control valves (10, 14). In the arrangement, pressure fluid is supplied to the percussion device (7) and the feed motor (11) by means of a volume flow adjusted pump (1). The arrangement further comprises control valves (10, 14) by means of which the volume flow of the pressure fluid fed by the pump (1) is kept such that the ratio of the pressure of the percussion device and that of the feed motor (11) remains substantially constant.

Abstract: A method of excavating a tunnel face in which the cutting head is sunk into the face to form an initial penetration and is then moved laterally. The power consumption of the cutting head drive motor is measured, compared with the setpoint value and the attack increment is controlled accordingly. The arm carrying the cutting head is swung at a maximum swing moment but the swing moment is reduced when monitored distortion of machine parts shows that this distortion has exceeded a predetermined value.

Abstract: A shearer-type mineral winning machine has three-phase a.c. motors on its main body for driving cutting drums and for propelling the machine along a mineral face. The frequency of the a.c. power supplied to the motor which serves to move the machine is varied and controlled in dependence on the operation of the cutting drums. Electronic control means for monitoring the performance of the cutting drums and for controlling the frequency of the a.c. power supplied to the machine drive motor are located in a control station in a protected position in a gallery remote from the machine and power is supplied to the machine via cables and/or bus bars.

Abstract: A mineral mining machine having haulage drive mechanism and at least one cutter drive unit for cutting elements which may be at each end of the mining machine. The cutting elements are driven by an electric motor through a variable speed gear-train and the haulage mechanism is driven by a hydraulic motor through a gear-train. The invention provides for a torque sensing device associated with a part of each cutter drive mechanism to sense the power transmitted by the cutter gear-train and a power sensing device associated with the electric motor. The torque sensing devices are in the form of a mechanical or electrical transducer which provides a signal when the power transmitted by the cutter gear-trains exceed or tends to exceed the rated value of the cutter gears. The signal is transmitted to a hydraulic pump to control the output to the hydraulic motor and thereby effect reduction of the haulage speed.

Abstract: Method and apparatus for controlling a mining machine, specifically a longwall mining machine, of the type in which the mining machine is advanced into a mineral seam by an advancing motor and a rotating mineral-cutting element on the machine is driven by a cutter drive motor. The invention resides in the realization that the specific cutting work of the machine, which is the work required to mine and remove a given unit of mined material, can be minimized by minimizing the differential quotient: ##EQU1## WHERE: N.sub.Wa is the driving power of the cutter drive motor; andV.sub.wi is the speed of the rotating mineral-cutting element.In carrying out the invention, the driving power of the cutter drive motor and the speed of the advancing motor are measured. From these quantities, the specific cutting work of the mining machine is computed and at least one of the aforesaid motors is controlled to minimize the specific cutting work.