Thermal Dynamics Corporation

Victor Equipment Company

Stephen W Norris

Roger W Hewett

David A Tatham

David Morrie

Roger M Chamberlin

Roger Chamberlin

A power supply is provided. The power supply in one form includes a rectifier circuit, a capacitor and an RC circuit. The rectifier circuit is configured to receive a three phase AC signal. The rectifier circuit has a positive output connected to a positive node and a negative output connected to a negative node. The capacitor is connected in parallel with the rectifier circuit between the positive node and the negative node. The RC circuit includes a resistor and capacitor connected in electrical series connection where the resistor and capacitor are connected between the positive node and the negative node in parallel with the first capacitor and the rectifier circuit.

High power factor rectifier/filter for three phase input welder or plasma cutter

A plasma arc torch system, a circuit, and a method for controlling a pilot arc is disclosed. A rate of change sensor, such as a dv/dt sensor, monitors an output current signal or an output voltage signal to determine whether to close a switch to re-attach a pilot arc before a transferred arc becomes extinguished. The switch selectively connects a tip into a circuit path with an electrode and a power supply to allow the pilot arc to form between the tip and the electrode. A power supply preferably regulates the output current or voltage to a first level when a pilot arc is present, and to a second mode when a transferred arc is present.

Plasma arc torch system with pilot re-attach circuit and method

A solenoid control and safety circuit suitable for use in connection with contact start, plasma-arc torches. The system monitors a voltage to determine when to open an air control solenoid as part of a contact starting process. If a proper voltage is sensed, a gas solenoid is opened to allow airflow to separate the contact starting elements. The system also includes a circuit that monitors a gas pressure switch to determine whether sufficient pressure exists to separate the contact start elements after a contact start process has been initiated. The circuit removes power if it senses insufficient pressure. Also disclosed is a circuit that monitors a differential voltage between the electrode and the tip to determine if the elements remain in contact after airflow has been provided to the torch head.

Solenoid control and safety circuit system and method

A plasm-arc torch system, a circuit, and a method for controlling a pilot arc. A rate of change sensor, such as a dv/dt sensor, monitors the output of an error amplifier to determine whether to close a switch to re-attach a pilot arc before a transferred arc becomes extinguished. The switch selectively connects a tip into a circuit path with an electrode and a power supply to allow the pilot arc to form between the tip and the electrode. The error amplifier preferably provides an error signal for use by a pulse-width modulator for providing a current regulated power supply capability. The power supply preferably regulates the output current to a first level when a pilot arc is present, and to a second mode when a transferred arc is present. The pilot arc may also be re-attached between the tip and the electrode by use of a pilot regulator that attempts to maintain the current flowing through the tip at an intermediate level between the first level and the second level. The pilot regulator is responsive to the total current flowing through the electrode but can only control that portion of the total current that flows through the tip.

Growing community of inventors

New London, NH, United States of America

Stephen W Norris