Patent ID: 8134819

Claim:
A single coil actuator for low and medium voltage applications comprising: a single coil electromagnet and a power and control unit operatively connected to said single coil electromagnet, said power and control unit comprising: a first control unit and a second control unit; a power input operatively connected to an input filter and rectifier; a power supply operatively connected to said input filter and rectifier and to said first and second control unit; a power circuit operatively connected to said single coil electromagnet; said first control unit being a microcontroller including analogue and digital inputs and outputs, said second control unit being a PWM controller which controls the current flowing in the single coil electromagnet through said power circuit, wherein said first control unit is operatively connected to said second control unit through a first output for setting the current flowing in said single coil electromagnet, wherein a second input of said first control unit is operatively connected to an output of said second control unit for measuring the output duty cycle of said PWM controller, wherein said first control unit is capable of calculating a change in the impedance in said single coil electromagnet on the basis of the measure of the output duty cycle of said PWM controller.