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Solenoid Reversing Circuit

IP.com Disclosure Number: IPCOM000091192D
Original Publication Date: 1969-Nov-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Stoddard, DL: AUTHOR [+2]

Abstract

This solenoid reversing circuit flushes the residual magnetism by a reversal in coil current thus causing not only removal of the residual magnetism but also a slight opposite polarity in magnetism to repel the armature during de-energization. The circuit can also serve as a direct replacement for the diode in a hot-shot circuit.

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Solenoid Reversing Circuit

This solenoid reversing circuit flushes the residual magnetism by a reversal in coil current thus causing not only removal of the residual magnetism but also a slight opposite polarity in magnetism to repel the armature during de- energization. The circuit can also serve as a direct replacement for the diode in a hot-shot circuit.

The circuit functions by first energizing the solenoid. Then in the on state, capacitor 10 is charged, while holding current is flowing through resistance element 12 and holding winding 14. Silicon controlled rectifier 26 does not conduct due to an absence of gate current. Switch 15 is opened and the voltage at such switch attempts to increase due to its inductance. Diodes 16 and 18 begin conducting and clamp the switch voltage to ground through resistor 20.

While diodes 16 and 18 are conducting, capacitor 22 is charged as a function of the resistor 20. A discharge path for capacitor 22 is then made through gate dropping resistor 24 and the gate of SCR 26 to its base and back to the other side of capacitor 22. Capacitor 10 discharges through resistor 12 and a positive voltage is on SCR 26. The gate current turns SCR 26 on and a path is then provided for current to flow from capacitor 10 through winding 14 in the opposite direction from its normal energized polarity. Capacitor 10 continues to maintain SCR 26 in an on condition until capacitor 10 is discharged. Thus, a reversing current is provided and the disch...