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Magnetic Actuator Drive Circuit

IP.com Disclosure Number: IPCOM000091473D
Original Publication Date: 1968-Feb-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Baumeister, HK: AUTHOR [+2]

Abstract

These magnet actuator drive circuits provide reduced holding current with no power dissipation, and external circuit components and, in addition, store energy for enhancing turnon. Two arrangements A and B of the circuit are shown.

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Magnetic Actuator Drive Circuit

These magnet actuator drive circuits provide reduced holding current with no power dissipation, and external circuit components and, in addition, store energy for enhancing turnon. Two arrangements A and B of the circuit are shown.

When switch S of circuit A is closed, the supply voltage E is impressed across resistor R1, inductor L1 and capacitor C1 in parallel with capacitor C2, resistor R2 and inductor L2 since diode D is reversed biased. This connection prevails until C1 and C2 become charged. At this time, D becomes forward biased and R1, L1, D, R2, and L2 are connected in series which causes the current through L1 and L2 to reduce to one half that of the initial value. When S is opened, C2 discharges through R1, L1 and D while C1 discharges through R2, L2 and D. The collapsing fields in L1 and L2 induce voltages which charge C1 and C2 with a polarity which aids turnon in the next subsequent cycle of operation.

In those instances where the duty cycle permits the stored charge to leak of f, a trickle charge can be applied to capacitors C1 and C2 as in circuit B. Operation is substantially that of circuit A, however, when switch S is opened, source E2 charges C1 and C2 to E2 - E1. The polarity is such that on the next cycle when S is closed, the charged capacitors are in series with source E1 to enhance turnon. Source E2 is effectively removed from the circuit when S is closed. Resistor R3 has a very high value and protects E2 w...