| 摘要 |
PURPOSE:To reduce power consumption, by providing a thermal response switch in series with a demagnetizing coil, in an automatic demagnetizer using a resistive element of positive temperature coefficient and a demagnetizing coil. CONSTITUTION:When a power supply switch 2 is closed, a comparatively large current flows to a demagnetizing coil via a resistive element 3 having a positive temperature coefficient. Since the element 3 is heated with this current, the current is reduced according to it and it is balanced at a temperature. Demagnetization is made with an AC current reduced like this. The operating current to a load circuit 9b is applied via a heating resistive element 10b of a thermal response switch 10. Thus, after a given time, a contact 10a is opened and a series circuit consisting of the element 3 and a coil 4 is detached from an AC power supply 1. Thus, after the end of demagnetization, since no current flows to the demagnetizing coil, unnecessary power loss can be avoided. |
