| 摘要 |
PURPOSE:To attempt to decrease apparent power by a method wherein a non-linear resistance element is connected to an electromagnetic coil in series and 80% or more of rated voltage is applied thereto so as to let the coil attract a moving iron core and then the voltage is suppressed to the extent that, after the iron core has been attracted, the coil can maintain the attracting condition due to a rise in resistance while holding down noise. CONSTITUTION:Since the resistance of a non-linear resistance element Rn is so low as is ignorable at the initial point of time if rated voltage is applied across terminals (a), (b), most part of the rated voltage is applied to an electromagnetic coil and a moving iron core 3 is attracted with sufficient attracting force. At this time, the non-linear resistance element Rn is heated by current (i) flowing through the circuit and the temperature rises. For this reason, the current is restricted by the resistance of the non- linear resistance element Rn and settles to current i0 having a preselected value. Accordingly, if the moving iron core 3 is prevented from being detached by selecting the non-linear resistance element Rn to allow the voltage applied after the current has gained the value of i0 to conform to more than 40%-50, or 60% of the rated voltage E which is the minimum necessary voltage for keeping the moving iron core 3 being attracted, the attracting condition with the current value i0 will be maintained, whereas noise will be reduced. |
