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High-Speed Magnet Switching Circuits

IP.com Disclosure Number: IPCOM000097405D
Original Publication Date: 1962-Nov-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 51K

Publishing Venue

IBM

Related People

Albosta, CA: AUTHOR

Abstract

In high-speed magnet construction, the objective is to decrease the number of coil turns to reduce the inductive time constant of the coil. However, this reduction in the number of turns must be limited to assure sufficient magnetic force and provide for heat dissipation, when high values of current are used. These two circuits enable rapid switching of a large inductance by circumventing the inductive rise time of a switching coil while maintaining a substantial number of of coil turns.

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High-Speed Magnet Switching Circuits

In high-speed magnet construction, the objective is to decrease the number of coil turns to reduce the inductive time constant of the coil. However, this reduction in the number of turns must be limited to assure sufficient magnetic force and provide for heat dissipation, when high values of current are used. These two circuits enable rapid switching of a large inductance by circumventing the inductive rise time of a switching coil while maintaining a substantial number of of coil turns.

Drawing A shows a simple electromagnet 1 with two connected coils 2 and 3 oppositely wound on the same leg 4 of a U-shaped core. These coils can be placed side-by-side on the leg, as shown, but are preferably interwound or overwound. Source 5 of D. C. voltage is connected across the non-adjacent ends of the respective coils. Switch S-1, interposed between the source 5 and coil 2, controls connection of the coils 2 and 3 with source 5. Switch S-2 is connected across coil 3. In series with switch S-2 is capacitor 6, shunted by resistor 7

As shown in drawing B at time t0, switch S-1 is closed to cause current flows I' and I through coils 2 and 3, respectively. Since coils 2 and 3 are oppositely wound, I' is opposite to I. Hence, flux generation is impeded by the oppositely flowing currents and zero flux results if the coils 2 and 3 have equal numbers of turns of the same size wire. If no flux is generated, the current rise is unopposed by inducta...