A system and method for shaping the trajectory of a motion command to reduce the effects of a load on performance of a motor dynamically modifies the motion profile in real time to limit the reference signals in the motion profile to feasible commands. A load observer determines an estimated disturbance acceleration. The estimated disturbance acceleration includes the dynamics of the controlled load and is used to modify a maximum and a minimum limit for the acceleration reference. The acceleration limits are, in turn, used to determine velocity limits. The motion profile and modified acceleration and velocity limits are provided to a state filter which determines a new motion profile for use by the motor drive to control operation of a motor and to control the load connected to the motor.

A system and method for shaping the trajectory of a motion command to reduce the effects of a load on performance of a motor dynamically modifies the motion profile in real time to limit the reference signals in the motion profile to feasible commands. A load observer determines an estimated disturbance acceleration. The estimated disturbance acceleration includes the dynamics of the controlled load and is used to modify a maximum and a minimum limit for the acceleration reference. The acceleration limits are, in turn, used to determine velocity limits. The motion profile and modified acceleration and velocity limits are provided to a state filter which determines a new motion profile for use by the motor drive to control operation of a motor and to control the load connected to the motor.

Examples described herein provide a method for overspeed protection of a motor of a gate crossing mechanism. The method includes monitoring, by an overspeed protection circuit, a voltage across a first Zener diode and a second Zener diode. An anode of the first Zener diode is connected to an anode of the second Zener diode. The method further includes, responsive to determining that a Zener voltage threshold is exceeded, allowing a current to flow into a gate pin of a triac. The triac controls the motor of the gate crossing mechanism.

Examples described herein provide a method for overspeed protection of a motor of a gate crossing mechanism. The method includes monitoring, by an overspeed protection circuit, a voltage across a first Zener diode and a second Zener diode. An anode of the first Zener diode is connected to an anode of the second Zener diode. The method further includes, responsive to determining that a Zener voltage threshold is exceeded, allowing a current to flow into a gate pin of a triac. The triac controls the motor of the gate crossing mechanism.

The invention relates to an electric machine tool comprising an electric motor, a motor control unit for operating the electric motor, an input interface for entering a target specification of an operating mode of the electric motor into the motor control unit, and a motor sensor device for detecting the operating mode of the electric motor. A slave control unit is provided, which is independent from the motor control unit and communicatingly connected to the motor sensor device and the input interface and designed to compare the operating mode of the electric motor detected by the motor sensor device with the target specification entered via the input interface, and to influence the operating mode of the electric motor in case of a defined deviation of the operating mode from the target specification by means of a control device.

The invention relates to an electric machine tool comprising an electric motor, a motor control unit for operating the electric motor, an input interface for entering a target specification of an operating mode of the electric motor into the motor control unit, and a motor sensor device for detecting the operating mode of the electric motor. A slave control unit is provided, which is independent from the motor control unit and communicatingly connected to the motor sensor device and the input interface and designed to compare the operating mode of the electric motor detected by the motor sensor device with the target specification entered via the input interface, and to influence the operating mode of the electric motor in case of a defined deviation of the operating mode from the target specification by means of a control device.

A blower in one aspect of the present disclosure includes: a housing including a first discharge port; a motor in the housing; a fan in the housing; an attachment fitting portion; and a motor drive circuit. The attachment fitting portion is configured to detachably attach, to the first discharge port, an attachment including a second discharge port. The motor drive circuit (i) delivers a designated power to the motor and (ii) performs a constant power control that maintains a magnitude of an electric power delivered to the motor at a magnitude of the designated power.

A blower in one aspect of the present disclosure includes: a housing including a first discharge port; a motor in the housing; a fan in the housing; an attachment fitting portion; and a motor drive circuit. The attachment fitting portion is configured to detachably attach, to the first discharge port, an attachment including a second discharge port. The motor drive circuit (i) delivers a designated power to the motor and (ii) performs a constant power control that maintains a magnitude of an electric power delivered to the motor at a magnitude of the designated power.

A blower in one aspect of the present disclosure includes: a housing including a suction port and a discharge port; a motor in the housing; a fan in the housing; a motor drive circuit; and a control circuit. The control circuit detects an insufficient airflow from the suction port to the discharge port based on an operation parameter. The operation parameter is associated with an operation of the motor.

An inverter device is provided. The inverter device converts power from a power source and drives a motor. The inverter device includes an inverter circuit having a switch, a driver circuit that switches the switch on and off, and a controller that controls the driver circuit. The controller has a speed calculator used to calculate a minimum speed of the motor based on a power source voltage. After the controller performs fail-safe control, when a speed of the motor is less than the minimum speed, the fail-safe control is ended.