The objective of the present invention is the provision of a current detection device which is capable of detecting current of a wide range by way of one magnetic core and which is capable of reliably detecting overcurrent at a time when the overcurrent flows. The present invention is provided with: an excitation coil (3) wound around a magnetic core (2) surrounding a conductive wire in which a measured current flows; and an oscillation circuit (4) which, in accordance with a set threshold, when the magnetic core (2) is in a saturated state or a state in the vicinity of the same, generates a rectangular voltage which inverts magnetization of an excitation current supplied to the excitation coil (3). Furthermore, the present invention is provided with a duty detection circuit (5) which detects a measured current on the basis of a duty change of the rectangular voltage that has been output from the oscillation circuit (4), a frequency detection circuit (7) which detects overcurrent of the measured current on the basis of the frequency of the rectangular voltage that has been output from the oscillation circuit (4), and an oscillation amplitude detection circuit (6) which detects overcurrent of the measured current on the basis of the peak value of the rectangular voltage that has been output from the oscillation circuit (4).

Current detection device

A current detecting device includes an exciting coil ( 3 ) wound around a magnetic core ( 2 ) enclosing a conductor through which flows a measurement current, and an oscillator circuit ( 4 ) that generates a square wave voltage which is supplied to the exciting coil ( 3 ). Furthermore, the current detecting device includes a duty detector circuit ( 5 ) that detects the measurement current based on variation in the duty ratio of the square wave voltage output from the oscillator circuit ( 4 ), a frequency detector circuit ( 7 ) that detects an overcurrent of the measurement current based on the frequency of the square wave voltage output from the oscillator circuit ( 4 ), and an oscillation amplitude detector circuit ( 6 ) that detects an overcurrent of the measurement current based on the magnitude of the square wave voltage output from the oscillator circuit ( 4 ).

Current detecting device

Electrical current transducer comprising a measuring circuit (6) and an inductor (4) for measuring a primary current /P flowing in a primary conductor (2), the inductor comprising a saturable magnetic core (10) made of a highly permeable magnetic material and a secondary coil (12) for carrying an alternating excitation i configured to alternatingly saturate the magnetic core, the coil being connected to the measuring circuit. The measuring circuit is configured to measure a mean value of the excitation current in the secondary coil and determine therefrom a value of the primary current for small current amplitudes, the measuring circuit being further configured for evaluating the frequency of the excitation current i and determining therefrom the value of the primary current for large currents.

Mixed mode fluxgate current transducer

The present invention relates to an autonomous electric power weeder comprising: a frame coupled with a handle for operation; an engine unit fixed onto the frame; a wheel mounted on the frame, and formed to roll on a work place; a speed reducing unit connected to an output axis of the engine unit, and reducing the number of rotation of the output axis to transfer electric power to the wheel; a distribution unit formed in the front of the frame, and formed to be able to distribute electric power of the output axis to a plurality of sub-output axes; and a weeding unit including a connection rod coupled with the distribution unit for each sub-output axis, a rotation axis coupled with the sub-output axis in the connection rod and formed to be able to be rotated, a cutter connected to an end of the connection rod and formed to be able to be rotated by the rotation axis, and a cover for protecting the cutter.

Self drving power weeder

PURPOSE: To decrease the number of parts and to reduce the device in size on the whole by detecting a current through the self-exciting operation of a magnetic semiconductor circuit consisting of a magnetic core with high magnetic permeability and an operational amplifier. CONSTITUTION: When the operational amplifier 9 is saturated positively and a positive voltage Vs developed at a terminal 8, the amplifier 9 keeps on sending a positive saturation voltage Vs to excite the magnetic core 1. The magnetic core 1 decreases in magnetic permeability before magnetic flux density attains to a maximum level and the impedance of winding 3 also decreases; and the voltage at a terminal 3a is inverted into a negative voltage owing to the resonance between a capacitor 6 and the winding 3 and inputted to an uninverted input terminal 10b, so that the voltage at the terminal 8 is switched automatically to a negative DC saturation voltage -Vs. Similarly, the voltage -Vs is changed to +Vs and DC voltages ±Vc applied to the amplifier 9 develop voltages ±Vs alternately at the terminal 8 with a voltage signal induced at the winding 3, and the positive/negative period length ratio of the voltage waveforms is controlled with the current to be measured. COPYRIGHT: (C)1985,JPO&Japio

Shinjiro Takeuchi

Papers

Self-oscillation type current sensor