| 摘要 |
PURPOSE:To obtain a device which is small, light and also exhibits excellent loading and unloading efficiency by charging switching means when demagnetization is carried out so that an electric current may flow in the second exciting coil in the opposite direction to the case of attracting, thereby controlling the current which flows in the first and second exciting coils at the prescribed timing after controlling the first and second rectifiers. CONSTITUTION:An electromagnet equipped with the first and second exciting coils 4a and 4b which connect to the first and second rectifiers 2 and 3, switching means 11 and 12, a controlling means 10, and the like and provided. In the case of attracting, the controlling means 10 controls the rectifiers 2 and 3 and the switching means 11 and 12 and permits a current to flow in the exciting coils 4a and 4b so that a magnetic flux generated by the first and second exciting coils 4a and 4b may exert on the same direction. In the case of demagnetization, the controlling means 10 charges the switching means 11 and 12 so that the current flows in the second exciting coils 4b, that is, in the opposite direction to the case of attracting and the first and second rectifiers 2 and 3 are controlled on the basis of electric current values which are detected with detecting means 7a and 7b and then the current flowing in the first and second exciting coils 4a and 4b are controlled at the prescribed timing.
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