| 摘要 |
<p>PURPOSE:To secure the safety by outputting a signal for the existence of overcurrent with fault in such a manner that a current with the phase having different zero points is supplied to the winding of saturable magnetic material which is crossed with the wire to supply a magnetic flux, at the same cycle as that of the current supplied to the wire. CONSTITUTION:An AC current (a) for driving a motor is supplied to a load (motor in this case) 3 at input terminals 1, 2 and also rectified (b) by a transformer T, then the amplitude is limited by a constant voltage diode 8. When this output is increased, a PUT(programmable unijunction transistor) oscillator including the PUT 6 is oscillated (c) after the specified time. This output pulse is amplified by a transistor 7 and supplied to the winding 10 of a core 4 of saturable magnetic material. The amplitude of this voltage is varied according to the current supplying state to feeders k1<2> and the output amplitude at a terminal 11 is varied. An output signal of the winding 10 is extracted by a winding 13 through the core 4, and the same signal (d) is obtained for the terminals 11, 15 in the case of different method from the terminal 11. Then the low level output signal indicating a danger is generated even in the case a disconnection fault is generated whichever in the windings 10 or 13.</p> |
