A controller executes a dither control that cyclically increases and decreases an exciting current in a linear solenoid valve so as to vibrate a spool of the linear solenoid valve. A vibration cycle of the spool obtained through the dither control is referred to a dither cycle. The dither control includes a first dither control that vibrates the spool in a first dither cycle and a second dither control that vibrates the spool in a second dither cycle that is shorter than the first dither cycle. The controller executes the first dither control and the second dither control when an oil temperature of the hydraulic oil is between a first oil temperature and a second oil temperature that is higher than the first oil temperature.

A method of controlling an actuator for a low power system, such as an irrigation system, where the actuator comprises a movable element and an electromagnetic coil for generating a magnetic field for displacing the movable element along the axis of the electromagnetic coil.

A controller executes a dither control that cyclically increases and decreases an exciting current in a linear solenoid valve so as to vibrate a spool of the linear solenoid valve. A vibration cycle of the spool obtained through the dither control is referred to a dither cycle. The dither control includes a first dither control that vibrates the spool in a first dither cycle and a second dither control that vibrates the spool in a second dither cycle that is shorter than the first dither cycle. The controller executes the first dither control and the second dither control when an oil temperature of the hydraulic oil is between a first oil temperature and a second oil temperature that is higher than the first oil temperature.

Disclosed is a method for closing the contacts of an electrical switching device during a switch-on process, wherein for a fixed first time period, the first time period and the first voltage being selected in such a way that the armature is not set into motion during the first time period, or the first voltage is applied to the coil until a certain current value is reached, the first time period being the time period until said certain current value is reached, and the first voltage being selected in such a way that the armature is not set into motion during the first time period, wherein a suitable second voltage is defined, the second voltage being greater than the first voltage and being applied to the coil during a second time period in order to move the armature from the open position into the closed position.

A solenoid and a solenoid control device, the solenoid control device including: a solenoid having a first coil, a variable resistor connected to one end of the first coil in series, and a second coil connected with the first coil in parallel; a drive device that drives the solenoid by supplying power to the dual coils; and a controller that controls the solenoid through the drive device.

A solenoid plunger movement detection system and method can include: detecting current supplied to a solenoid with a current sensor; converting the current supplied to the solenoid into a digital signal with a counter coupled to a first comparator; detecting a peak within the digital signal with a peak detector; comparing the peak to the digital signal with a second comparator coupled to the peak detector; measuring a dip from the peak and measuring a trough with the second comparator; generating a fault when the peak and the trough indicate a smooth current ramp to the solenoid; receiving configurable parameters for processing the digital signal with a signal processor; and providing configurable parameters to the counter, the second comparator, the signal processor, or a combination thereof with an interface.

There is a solenoid including a stator having a first stator tooth and a second stator tooth, and an armature having a first armature tooth and a second armature tooth. The armature is moveable with respect to the stator over a predetermined stroke. A coil is associated with one of the stator and the armature for conducting an electric current and generating magnetic flux that is guided by the stator and the armature. The stator or the armature acts as a ferromagnetic core for the coil. There is a first air-gap between the first stator tooth and the first armature tooth that has a first length, and a second air-gap between the second stator tooth and the second armature tooth that has a second length. The first and second lengths are constant to within a predetermined margin over the predetermined stroke when the first and second armature teeth overlap the first and second stator teeth respectively.

A diagnostic method for diagnosing a malfunction of a solenoid valve includes: a) storing reference features of a solenoid current waveform, b) detecting features of the solenoid current waveform during operation of the solenoid valve, c) comparing the reference features with the detected features, d) comparing the pressure value of fluid entering the solenoid valve inlet orifice with a predetermined range of pressure values in the event of deviation between the value of the detected features and the value of the reference features, e) adjusting the pressure value and repeating steps b) and c) in the case of deviation of the pressure value with respect to the pressure value range, and f) generating an alarm signal due to malfunction of the solenoid valve in the event of a deviation between the value of the detected features and the value of the reference and fluid pressure features within the pressure value range.

Systems and methods for a solenoid supervisory detection system which can detect the presence or absence of a solenoid plunger within a solenoid coil. These systems can be used to verify correct reassembly of a solenoid valve after it has been disassembled for testing.

A bistable electromagnetic actuator is described. The actuator includes a mobile assembly and a fixed assembly. The mobile assembly includes at least one pair of ferromagnetic plunger-cores, a frame integrally connecting the plunger-cores, and a guiding element. The fixed assembly includes a ferromagnetic core having cavities defined on each of its two sides configured to receive a corresponding one of the plunger-cores, at least one magnet positioned between the cavities in the core and being able to create a first magnetic flux, at least one coil operable via an excitation current to create a second magnetic flux, and a guiding element adapted to cooperate with the guiding element of the mobile assembly to allow the mobile assembly to move between a first and a second stable position. Methods for actuating the bistable electromagnetic actuator are also described.