| 摘要 |
<p>PROBLEM TO BE SOLVED: To enhance an energizing efficiency by improving a power supply feeding method to an electromagnetic equipment such as an electromagnetic clutch, and an electromagnetic brake, lower the effective value of a energizing current, and make a coil and a snubber element small in size. SOLUTION: When the coil 23 of an electromagnetic clutch is to be energized, voltage from a commercial AC power supply rectified in full wave, is applied to the coil at the over exciting time when energization is started for the definite period of time so as to allow responsiveness at the time of starting to be enhanced. In succession, at the normal time, full wave rectified voltage whose conduction angle is controlled by a FET 25, is applied to the coil. Since voltage is rectified in full wave, its effective value is small as compared with that of half wave rectification in the past, the exothermic of the coil 23 is thereby little. Besides, electromagnetic energy to be accumulated in the coil 23 at the time when electricity is turned off, is also little. Therefore, it is good enough that a varister 26 acting as a snubber element is made small in size.</p> |
