A method for determining the position of an armature of an electromagnet, a method for determining the position of a valve member of an electromagnetically actuated fluid valve, and a fluid system comprising an electromagnetically actuated fluid valve and an electronic control unit executing the method for determining the position of a valve member are provided. The electronic control unit applies a current profile in the coil of a non-actuated electromagnet that is substantially below a minimum actuation current of the electromagnet. By applying the current profile, the electronic control unit determines a characteristic profile of the electromagnet. A position characteristic of the electromagnet is calculated based on the position characteristic.

A solenoid assembly includes a solenoid having a coil that defines a passageway and a plunger movable within the passageway from a retracted position to an extended position. The plunger extends along an axis between a first plunger end and an opposite second plunger end. A frame holds the solenoid and has a first opening through which the first plunger end extends when the plunger is in the retracted position and a second opening through second end of the plunger extends when the plunger is in the extended position. When the plunger is in the extended position the first plunger end retracts into the frame via the first opening.

A method is for operating a valve that includes a linearly movable control slide, at least one solenoid, and a position sensor. The linearly movable control slide is preloaded by at least one spring in a direction of a zero position. The at least one solenoid is coupled to the control slide in such a way that the control slide can be moved away from the zero position by application of current to the solenoid. The position sensor is configured to measure an actual instantaneous position of the control slide. Each solenoid is assigned a current control device configured to influence a current through the relevant solenoid based on an instantaneous current control variable. The instantaneous current control variable is dependent on a quasi-periodic dither current control variable. The method also includes calculating an actual dither amplitude from the actual instantaneous position using a band-pass filter.

An automatic leveling device of a 3D printer, and a 3D printer is provided. The automatic leveling device includes a photoelectric switch, an electromagnetic assembly and a probe assembly. The photoelectric switch is arranged in a housing and defines a photosensitive groove. The electromagnetic assembly is arranged in the housing and defines a sliding hole. The probe assembly is slidably engaged in the sliding hole, and an end of the probe assembly is engaged in the photosensitive groove. The electromagnetic assembly is capable of driving the probe assembly to make the end of the probe assembly move out of the photosensitive groove. The automatic leveling device has the advantages of simple structure, low manufacturing difficulty, low production cost, simple and stable leveling mode, high detection repetition accuracy and no complex circuit and software cooperation.

Disclosed are a solenoid actuator and a multi-stage solenoid actuator for transmitting a constant force. The solenoid actuator includes a tubular solenoid, a power unit capable of applying current to the solenoid, and a magnetic pair member having two magnetic members providing magnetic fields formed such that respective first poles thereof face each other and respective second poles thereof different from the first poles are located at both distal ends, and extending through the tub of the solenoid. The multi-stage solenoid actuator includes a solenoid assembly where at least two tubular solenoids are regularly aligned such that inner spaces of the tubes of the solenoids are arranged in series, a power unit capable of individually applying current to each solenoid of the solenoid assembly, at least one magnetic pair moveable unit having two magnetic members providing magnetic fields formed such that respective first poles thereof face each other and respective second poles thereof different from the first poles are located at both distal ends, and extending through the tub of the solenoid assembly, and a controller for determining and controlling a solenoid to receive the current from the power unit depending on a position of the magnetic pair moveable unit.

A system may include an armature configured to move between a first position that electrically couples the armature to a first contact and a second position that electrically couples the armature to a second contact. The system may also include a coil configured receive a current, such that the current conducting in the coil is configured to magnetize a core. The magnetized core may cause the armature to move from the first position to the second position. The system may also include a control system configured to detect a position of the armature based on an inductance of the coil.

Disclosed herein are reluctance actuators and methods for feedback control of their applied force. Embodiments of the reluctance actuators include an electromagnet positioned to deflect a metallic plate to provide a haptic output. The control of the force is provided without force sensors (sensorless control) by monitoring voltage and/or current (V/I) applied during an actuation. For a given intended force output, an electrical parameter value (flux, current, or other parameter) is read from a look up table (LUT). The LUT may store a present value of the inductance of the reluctance actuator. The feedback control may be a quasi-static control in which the LUT is updated after actuation based on the monitored V/I. The feedback control may be real-time, with a controller comparing an estimated electrical parameter value based on the measured V/I with the value from the LUT.

A structure for closing an actuator in a magnetically actuated switch assembly, where the actuator includes an armature and a winding, and the switch assembly includes a manual actuation device coupled to one end of the armature and a movable terminal in a vacuum interrupter coupled to an opposite end of the armature. The structure includes commencing a closing operation of the actuator using the manual actuation device to move the armature towards a closed latch position, detecting that the actuator is being manually closed, and energizing the winding to assist moving the armature to the closed latch position when the armature gets to a predetermined distance from the closed latch position.

The semiconductor device controls the first circuit for supplying/stopping the current supplied by a DC power supply to the latching solenoid consisting of a coil and a movable iron core and a permanent magnet, the current is measured based on the input from the current detection circuit. The semiconductor device includes a control circuit having a low power dissipation mode in which the leakage current is reduced, and a normal operation mode. The control circuit maintains the low power consumption mode when no current is flowing through the coil, when a current is flowing through the coil maintains the normal operation mode, further, the movable iron core It comprises a control circuit configured to detect the inflection point of the current detected by the current detection circuit when leaving the permanent magnet.

Disclosed herein are reluctance actuators and methods for feedback control of their applied force. Embodiments of the reluctance actuators include an electromagnet positioned to deflect a metallic plate to provide a haptic output. The control of the force is provided without force sensors (sensorless control) by monitoring voltage and/or current (V/I) applied during an actuation. For a given intended force output, an electrical parameter value (flux, current, or other parameter) is read from a look up table (LUT). The LUT may store a present value of the inductance of the reluctance actuator. The feedback control may be a quasi-static control in which the LUT is updated after actuation based on the monitored V/I. The feedback control may be real-time, with a controller comparing an estimated electrical parameter value based on the measured V/I with the value from the LUT.