Provided are embodiments for determining solenoid plunger position by performing a method which includes generating, by a first signal circuit, a first signal based at least in part on a pull-in current value of a current applied to a solenoid coil of a solenoid. The method further includes generating, by a second signal circuit, a second signal by applying a time delay to the first signal. The method further includes comparing, by a comparator circuit, the first signal and the second signal to determine whether a plunger of the solenoid has moved within the solenoid from a first position to a second position. The method further includes, responsive to determining that the plunger of the solenoid has moved within the solenoid from the first position to the second position, reducing the current applied to the solenoid coil of the solenoid from the pull-in current value to a hold current value.

A drive circuit is controlled when power is interrupted. When power is turned off, a main power supply is switched to a sub-power supply, and a residual charge of a step-up circuit is lowered to a drive voltage of a drive circuit using a step-down circuit is used as the sub-power supply.

Magnet assemblies comprising a housing with a top plate each comprising aligned openings are described. The housing has a bottom ring and an annular wall with a plurality of openings formed in the bottom ring. The top plate is on the housing and has a plurality of openings aligned with the plurality of openings in the bottom ring of the housing. The magnet assembly may also include a non-conducting base plate and/or a conductive cover plate. Methods for using the magnet assembly and magnetic field tuning are also described.

Magnet assemblies comprising a housing with a top plate each comprising aligned openings are described. The housing has a bottom ring and an annular wall with a plurality of openings formed in the bottom ring. The top plate is on the housing and has a plurality of openings aligned with the plurality of openings in the bottom ring of the housing. The magnet assembly may also include a non-conducting base plate and/or a conductive cover plate. Methods for using the magnet assembly and magnetic field tuning are also described.

A method to estimate the temperature of an electromagnetic actuator, which entails a preliminary step in which to define a first threshold value for the current or for the voltage; and define a characteristic curve of the actuator family in the plane temperature/time needed to reach the threshold value; a step in which to carry out a reference measurement, in which, using the characteristic curve, a reference time needed by the electromagnetic actuator to reach the first threshold value is associated with a known reference temperature; and a step in which to carry out a series of measurements in which to determine the time needed by the electromagnetic actuator to reach the first threshold value, calculate the deviation between the time needed by the electromagnetic actuator to reach the first threshold value and the reference time; and determine the temperature of the electromagnetic actuator, using the characteristic curve, by associating the temperature of the electromagnetic actuator with the sum of the deviation and of the reference time.

A driving module comprises: a housing; a housing; a solenoid comprising a shaft arranged inside the housing so as to make a straight movement; and a printed circuit board arranged on the solenoid, wherein the solenoid comprises a stator, a plunger arranged inside the stator, a shaft coupled to the plunger, and a sensor magnet arranged on the upper side of the shaft, and the printed circuit board comprises a hole penetrated by the shaft and comprises a position detecting sensor arranged on the printed circuit board to be adjacent to the hole.

A constant-current control circuit comprising a switching circuit including a source voltage, and primary and secondary switches is provided. The primary GaNFET switch is connected with a solenoid assembly coil. The secondary switch is connected with the coil which has an inductance. From t.sub.0 to t.sub.on, the primary GaNFET switch is closed and the secondary switch is open, the source voltage is applied across the coil, and a counter EMF decays until the voltage across the coil equals the source voltage at t.sub.on, thereby allowing current to flow through the coil. From t.sub.on to T, the primary GaNFET switch is open and the secondary switch is closed, and a positive EMF equal to the source voltage is applied across the coil until the positive EMF decays to zero at T, such that the current continues to flow through the coil without the source voltage being applied across the coil.

Methods and systems are provided for a solenoid actuator. In one example, a method may include adjusting a switching frequency during an activation cycle of the solenoid actuator to a lower switching frequency relative to other phases of the activation cycle.

A test bench for a contactor bulb includes: a frame, configured to fix the bulb therein, and an actuation device, borne by the frame and including an output shaft, centred on a longitudinal axis and translationally movable with respect to the frame parallel to the longitudinal axis between a front position and a rear position, the output shaft being configured to be connected to an actuation rod of the bulb. The actuation device is a moving magnet electromagnetic actuator.

A fluid dispensing device and method for controlling the device are provided. The device includes a housing defining a fluid outlet. A valve controls the flow of fluid to the outlet. A sensor is configured to detect an object outside of and proximate to the housing. A solenoid is configured to move the valve between an open position and a closed position. A controller is configured to receive the output signal of the sensor, determine a characteristic of noise in the output signal such as a level of noise, adjust at least one of a sampling rate of the output signal and an amount of filtering of the output signal responsive to the characteristic of noise in the output signal, and transmit a control signal to the solenoid responsive to the output signal.