EXCITATION AND EXCITATION POWER SOURCE DEVICE OF DIRECT-CURRENT ELECTROMAGNET

摘要

PURPOSE:To obtain a small and inexpensive device without decreasing the performance by connecting an excitation DC power source and an excitation DC power source selectively to a DC electromagnet. CONSTITUTION:An excitation DC power source 12 for small-capacity reverse excitation to eliminate the hysteresis characteristic of a DC electromagnet 7 and eliminate a magnetic field and a regular excitation DC power source 11 are connected directly to the DC electromagnet 7 through a reflex prevention changeover switch 6. The excitation DC power source 12 is excited after the operating duty of the electromagnet finishes and then a current passed through the regular excitation DC power source 11 is eliminated, and accurately supplies a current of value -IR required for obtaining a zero field determined by the hysteresis characteristic of the electromagnet. Thereby a high-accuracy zero field out of the operating duty of the electromagnet 7 is obtained and the capacity and the price of the whole device are reduced.