The application provides a method and device for adjusting a permanent magnet motor, an equipment, and a storage medium. The method includes the following operations. An electronic equipment acquires a counter electromotive force (CEMF) parameter, information of an electromagnetic structure of a permanent magnet motor to be adjusted and a minimum impedance value of any short-circuited coil of the permanent magnet motor to be adjusted, to determine an operational time of the short-circuited coil. The electronic equipment further judges, according to the operational time of the short-circuited coil, whether an adjustment instruction is required to be transmitted to a production equipment. When the operational time is inconsistent with a preset time, the electronic equipment transmits the adjustment instruction to the production equipment. The production equipment adjusts, according to the adjustment instruction, the electromagnetic structure of the permanent magnet motor to be adjusted. Through the method of the application, a rail transit vehicle may keep running for the preset time safely after an inter-turn short circuit failure occurs to the permanent magnet motor, and the operational safety of the rail transit vehicle is improved.

A power tool is provided including a brushless direct-current (BLDC) electric motor having a stator and a rotor. The power tool includes power switches including high-side switches and low-side switches disposed on a direct-current (DC) bus line between a power supply and the electric motor, and a controller configured to electronically brake the motor by simultaneously closing the high-side switches or the low-side switches to electrically short the stator windings. In an embodiment, the controller is configured to monitor a voltage of the DC bus line, and if the voltage of the DC bus line is lower than a voltage threshold, execute electronic braking by toggling between closing the high-side switches and closing the low-side switches over braking cycles, and if the voltage of the DC bus line is greater than the voltage threshold, execute braking by closing only the high-side switches or the low-side switches over the braking cycles.

An axial field rotary energy device has a PCB stator panel assembly between rotors with an axis of rotation. Each rotor has a magnet. The PCB stator panel assembly includes PCB panels. Each PCB panel can have layers, and each layer can have conductive coils. The PCB stator panel assembly can have a thermally conductive layer that extends from an inner diameter portion to an outer diameter portion thereof. Each PCB panel comprises discrete, PCB radial segments that are mechanically and electrically coupled together to form the respective PCB panels.

An axial field rotary energy device has a PCB stator panel assembly between rotors with an axis of rotation. Each rotor has a magnet. The PCB stator panel assembly includes PCB panels. Each PCB panel can have layers, and each layer can have conductive coils. The PCB stator panel assembly can have a thermally conductive layer that extends from an inner diameter portion to an outer diameter portion thereof. Each PCB panel comprises discrete, PCB radial segments that are mechanically and electrically coupled together to form the respective PCB panels.

An electronic rotary encoder is configured to be disposed on a vertical rotary shaft in a rotary object to obtain two encoded signals: a phase A signal and a phase B signal for calculating a rotational speed and a position. The electronic rotary encoder includes: at least one Hall element outputting Hall signals used as a square wave of the phase A signal; two capacitors, to respectively obtain a first voltage and a second voltage; two buffer gates, to respectively output waveform signals of a first X voltage and a second X voltage; two comparators outputting, a control signal through a latch; and an exclusive OR gate, where a direction signal and the control signal outputted through the latch are inputted to the exclusive OR gate, to obtain the phase B signal.

An electronic rotary encoder is configured to be disposed on a vertical rotary shaft in a rotary object to obtain two encoded signals: a phase A signal and a phase B signal for calculating a rotational speed and a position. The electronic rotary encoder includes: at least one Hall element outputting Hall signals used as a square wave of the phase A signal; two capacitors, to respectively obtain a first voltage and a second voltage; two buffer gates, to respectively output waveform signals of a first X voltage and a second X voltage; two comparators outputting, a control signal through a latch; and an exclusive OR gate, where a direction signal and the control signal outputted through the latch are inputted to the exclusive OR gate, to obtain the phase B signal.

A long-distance speed control system for a brushless DC motor of a fan is provided. The long-distance speed control system includes a switch connected with a mains power supply, a switch circuit, a voltage detection module, a power cord, a processing unit, and a drive unit, which can control the multi-stage rotational speed of the motor. In the field of brushless DC motors for fans, there is no need to use analog-to-digital conversion chips between the mains power supply and the processor, having the advantages of low cost, environmental protection, and reduction of waste of earth resources. Besides, the switch, the switch circuit and the power cord can withstand the mains power supply, having the advantages of less signal attenuation and long-distance transmission.

A long-distance speed control system for a brushless DC motor of a fan is provided. The long-distance speed control system includes a switch connected with a mains power supply, a switch circuit, a voltage detection module, a power cord, a processing unit, and a drive unit, which can control the multi-stage rotational speed of the motor. In the field of brushless DC motors for fans, there is no need to use analog-to-digital conversion chips between the mains power supply and the processor, having the advantages of low cost, environmental protection, and reduction of waste of earth resources. Besides, the switch, the switch circuit and the power cord can withstand the mains power supply, having the advantages of less signal attenuation and long-distance transmission.

The invention relates to a device for reducing harmful bearing voltages in an electrical machine (M) fed by a DC link voltage of a DC link, said electrical machine comprising a stator (3), which has windings (7) and is insulated from ground (GND), and a rotor (2) and a motor shaft, wherein furthermore a rotor-side bearing (LA.sub.R) and a stator-side bearing (LA.sub.S) are each insulated from the ground (GND) and the rotor (2) and the stator (3) are electrically connected to each other by means of a bypass capacitance (C.sub.Bypass) having a predefined capacitance.

The invention relates to a device for reducing harmful bearing voltages in an electrical machine (M) fed by a DC link voltage of a DC link, said electrical machine comprising a stator (3), which has windings (7) and is insulated from ground (GND), and a rotor (2) and a motor shaft, wherein furthermore a rotor-side bearing (LA.sub.R) and a stator-side bearing (LA.sub.S) are each insulated from the ground (GND) and the rotor (2) and the stator (3) are electrically connected to each other by means of a bypass capacitance (C.sub.Bypass) having a predefined capacitance.