38results about How to "Fast demagnetization" patented technology

The invention relates to a power unit for an electronic jacquard needle selecting mechanism. The power unit comprises an iron core, a concentrating flux sleeve, a movable armature and an elastic component, wherein the concentrating flux sleeve sleeves the iron core, and a coil is arranged between the concentrating flux sleeve and the iron core; the movable armature sleeves the iron core, the movable armature and the concentrating flux sleeve are attracted with each other when the coil is electrified; the elastic component is used for resetting the concentrating flux sleeve and the movable armature. Compared with the prior art, the power unit for the electronic jacquard needle selecting mechanism has the following beneficial effects that the structure is simple, a relatively large needle number on a unit area can be obtained, and the dense arrangement can be achieved, so that the unit cost is reduced; furthermore, the integration level can be improved.

The present invention relates to the electric power automation technology, and aims to provide a demagnetizing circuit and method for removing residual magnetism of an electromagnetic current transformer on line. The demagnetizing circuit comprises a series connection structure formed by a third resistor and an inductor, a third switch is also connected in parallel at two ends of the inductor, the series connection structure is connected in parallel at two ends of a secondary side of a current transformer with a second resistor and a first switch, an outer end of the third resistor is earthed, an outer end of the inductor is connected to one end of a direct current power supply through a second switch, the other end of the direct current power supply is earthed, and a first resistor is disposed between the second resistor and a non-earthing end of the first switch. With adoption of the circuit and the method, the residual magnetism inside the current transformer is removed within a very short time when the switches are disconnected, and the accuracy of relay protection setting calculation and the reliability of relay protection actions are raised. The residual magnetism can be removed on line, and the current transformer does not need to be out of service. No complicated signal detection circuits or control circuits are required, and the circuit is easy to realize. The error of residual magnetism of an iron core after demagnetizing is small, and the demagnetizing speed is high.

The invention relates to an SRM direct instantaneous torque control method for dynamic adjustment of DC bus voltage. The method adds a DC-DC conversion circuit at the front end of a traditional asymmetrical half-bridge power converter, and decouples the excitation path and the demagnetization path, and can apply more The high demagnetization voltage makes the winding of the switched reluctance motor demagnetize faster. According to the different operating speeds of the switched reluctance motor, the DC bus voltage of the power converter is adjusted accordingly, and the adjustment method has an optimized opening angle. Features: The commutation rule of the switched reluctance motor is improved, and the commutation conduction zone performs direct instantaneous torque control through a higher demagnetization voltage to reduce torque ripple while taking into account the optimal opening angle characteristics; the switched reluctance motor In the operating range of full speed, the torque ripple is reduced by a control strategy of direct instantaneous torque control without switching control strategy.

The invention discloses a demagnetizing device of an electric magnet, which comprises a working magnet core, an electromagnetic coil and an electromagnetic coil operating control circuit. The electromagnetic coil is also communicated with a current attenuation oscillating circuit, the current attenuation oscillating circuit is connected with the electromagnetic coil operating control circuit in parallel, and a control relay for controlling the electric magnet through working current and attenuation oscillating current is communicated to the electromagnetic coil operating control circuit; after the direct current electric magnet of the electromagnetic coil is powered off, an alternating current power supply charges power to a charging capacitor through the current attenuation oscillating circuit and the electromagnetic coil, along with the continuous increase of the voltage at the both ends of the charging capacitor, the charging current is lower and lower, and the current passing through the electromagnetic coil is alternate, thereby the purpose that an electromagnetic cylinder is fast demagnetized is achieved. Through the improvement, the remnant magnetism problem of the electromagnetic coil is solved, thus a bunker scale can be automatically reset after being used for a long time, and the labor productivity is improved.

The invention relates to a control circuit for a synchronous machine (1) of a dental handpiece, comprising a voltage supply (2) and a clamping circuit (7) connected by switches (6). The invention also relates to a method for determining an angular position of a rotor of a synchronous machine (1), wherein a power supply is switched off for a total period of time (T2), a clamping circuit (7) is connected for a time interval (T1), whereupon an electromotive force is measured, and the angular position is determined from the electromotive force.

The invention relates to a novel intelligent electronic coil. The novel intelligent electronic coil is characterized in that one output end of a full bridge rectifying circuit is connected into a low power dissipation processor through a voltage sampling circuit, the other output end of the full bridge rectifying circuit is connected with the input end of a self-powered circuit and connected into the output end of a follow current demagnetization loop through one end of an exciting coil, and the reference end is grounded; one output end of the self-powered circuit is connected with one input end of the low power dissipation processor, the other output end of the self-powered circuit is connected to a first driving circuit, the other input end of the low power dissipation processor is connected with a current sampling circuit, one end of the current sampling circuit is connected with reference end of the self-powered circuit and grounded, the other end of the current sampling circuit is connected with a first switch tube, two output ends of the low power dissipation processor are connected into the follow current demagnetization loop and the first switch tube through driving circuits respectively, and the other end of the follow current demagnetization loop is connected with the first switch tube through the other end of the exciting coil. The novel intelligent electronic coil has the advantages of being small in size, wide in voltage input, suitable for both alternating current and direct current, fast to break, reliable in work and the like.