Solid-state degauss circuit for use in an electromagnetic lock
AssigneeHanchett Entry Systems, Inc.
InventorRandall Shaffer
Life of this patent
Estimating the term…
Abstract
A novel and useful solid-state degauss circuit for use with electromagnetic door locks. The door lock circuit is configured to provide a current to the electromagnetic coil load. A pulse width modulation (PWM) controller varies the frequency and/or duty cycle to a switch in series with the coil. An active, solid-state degauss circuit in line with the current flowing through the coil is provided. When triggered either in an uncontrolled or controlled manner, the active degauss circuit composed of a solid-state device, creates a short circuit across the coil after current reversal is achieved thereby degaussing.
Claims19
A method of degaussing an electromagnet of an electromagnetic door lock, the method comprising:
- providing a controller configured to control a current flow through an electromagnetic coil of the electromagnet;
- providing at least one resistor in line with at least one first capacitor in electrical connection between a first lead of the electromagnetic coil and a ground;
- providing a diode in line with a transistor in electrical connection with the first lead of the electromagnetic coil and the ground and electrically parallel with the at least one resistor in line with the at least one capacitor;
- reversing the current flow through the electromagnetic coil;
- and
- while reversing the current flow through the electromagnetic coil, performing a degaussing operation on the electromagnet,
- wherein performing the degaussing operation comprises switching on the transistor in electrical connection with the first lead of the electromagnetic coil to form a short circuit from the first lead of the electromagnetic coil to the ground.
A system for degaussing an electromagnet of an electromagnetic door lock, the system comprising:
- a controller configured to control a current flow through an electromagnetic coil of the electromagnet;
- at least one resistor in direct electrical connection with a first lead of the electromagnetic coil of the electromagnet;
- at least one first capacitor electrically connected in line with the at least one resistor and in electrical connection with a ground;
- a diode in direct electrical connection with the first lead of the electromagnetic coil of the electromagnet;
- and
- a transistor electrically connected in line with the diode and in electrical connection with the ground, wherein the transistor electrically connected in line with the diode is connected electrically parallel with the at least one resistor in line with the at least one capacitor
- wherein the transistor is configured to switch on to form a short circuit from the first lead of the electromagnetic coil to the ground thereby degaussing the electromagnet.
A method of degaussing an electromagnetic coil, the method comprising:
- providing at least one resistor in line with at least one capacitor in electrical connection with a first lead of the electromagnetic coil and a ground;
- providing a diode in line with a transistor in electrical connection with the first lead of the electromagnetic coil and the ground and electrically parallel with the at least one resistor in line with the at least one capacitor;
- and
- performing a degaussing operation on the electromagnetic coil by switching on the transistor to form a short circuit from the first lead of the electromagnetic coil to the ground.
Dependencies are inferred from the claim text.