Patent ID: 6650113
Filing Date: 2003-11-18
Classification: G01R

Abstract:
A magnetic flux detector comprising:a magnetic flux generator, which includes an exciting coil and generates a magnetic flux when an excitation current is supplied to said excitation coil; an excitation current controller, which controls said excitation current being supplied to said exciting coil; a search coil, which is placed in a magnetic path where the magnetic flux generated by said magnetic flux generator passes, such that an electromotive force is induced in said search coil in response to a change in the magnetic flux; and a magnetic flux calculator, which determines the magnitude of the magnetic flux generated by said magnetic flux generator by measuring the electromotive force induced in said search coil; wherein: said excitation current controller controls said excitation current to increase from zero to a predetermined current value during a first predetermined time period and then to decrease from the predetermined current value to zero during a second predetermined time period; and said magnetic flux calculator determines the magnitude of the magnetic flux generated by said magnetic flux generator based on a difference between an increasing electromotive force integral value which is calculated by integrating the electromotive force induced in said search coil during said first predetermined time period and a decreasing electromotive force integral value which is calculated by integrating the electromotive force induced in said search coil during said second predetermined time period.