Patents by Inventor Thomas Lai Wai Ma
Thomas Lai Wai Ma has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 7257146Abstract: A method and system for stabilizing energy consumption in multiple loads, or in single multi-phase loads. The method and system also compensates for unbalance in multi-phase loads. A central controller monitors variable reactances in the loads and identifies situations of power and/or current fluctuation and/or unbalance. It determines appropriate corrective action by the other loads/phases to compensate for the power and/or current change or unbalance due to the problematic load, and it issues control signals instructing variable reactor controllers associated with the other loads to adjust accordingly. The method and system may by applied to electric arc furnace installations. The system and method may be employed to maintain a predetermined level of unbalance in the system.Type: GrantFiled: September 1, 2005Date of Patent: August 14, 2007Assignee: Hatch Ltd.Inventors: Mohammad Sedighy, Thomas Lai Wai Ma
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Patent number: 7212561Abstract: A method and system for stabilizing energy consumption in multiple loads, or in single multi-phase loads. The method and system also compensates for unbalance in multi-phase loads. A central controller monitors variable reactances in the loads and identifies situations of power and/or current fluctuation and/or unbalance. It determines appropriate corrective action by the other loads/phases to compensate for the power and/or current change or unbalance due to the problematic load, and it issues control signals instructing variable reactor controllers associated with the other loads to adjust accordingly. The method and system may by applied to electric arc furnace installations. In this context, the method and system provide an electrode position controller coupled to the feed rate controller so as to predictively anticipate the introduction of new source material and lower the electrodes so as to prevent arc extinguishment while the variable reactors maintain predetermined power set-points.Type: GrantFiled: August 31, 2005Date of Patent: May 1, 2007Assignee: Hatch Ltd.Inventors: Mohammad Sedighy, Thomas Lai Wai Ma
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Patent number: 7212562Abstract: A method and system for stabilizing energy consumption in multiple loads, or in single multi-phase loads. A central controller monitors variable reactances in the loads and identifies situations of power and/or current fluctuation and/or unbalance. The central controller determines appropriate corrective action by the other loads/phases to compensate for the power and/or current change or unbalance due to the problematic load, and it issues control signals instructing electrode position controllers associated with the other loads to adjust accordingly. The method and system may by applied to electric arc furnace installations. The electrode position controllers may be used in conjunction with variable reactance control systems to take corrective action to address power and/or current changes or unbalances. The variable reactors respond orders of magnitude faster than the electrode positioning system.Type: GrantFiled: September 1, 2005Date of Patent: May 1, 2007Assignee: Hatch Ltd.Inventor: Thomas Lai Wai Ma
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Publication number: 20060050760Abstract: A method and system for stabilizing energy consumption in multiple loads, or in single multi-phase loads. The method and system also compensates for unbalance in multi-phase loads. A central controller monitors variable reactances in the loads and identifies situations of power and/or current fluctuation and/or unbalance. It determines appropriate corrective action by the other loads/phases to compensate for the power and/or current change or unbalance due to the problematic load, and it issues control signals instructing variable reactor controllers associated with the other loads to adjust accordingly. The method and system may by applied to electric arc furnace installations. In this context, the method and system provide an electrode position controller coupled to the feed rate controller so as to predicatively anticipate the introduction of new feed material and lower the electrodes so as to prevent arc extinguishment while the variable reactors maintain predetermined power set-points.Type: ApplicationFiled: September 1, 2005Publication date: March 9, 2006Inventor: Thomas Lai Wai Ma
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Patent number: 6603795Abstract: A power control system for an AC electric arc furnace. The control system includes variable reactors located intermediate a furnace power supply and arc electrodes that are height adjustable. The control system monitors operating characteristics of the furnace that are indicative of the active power consumption of the furnace and adjusts the variable reactors and the electrode height so as to minimize variations in the active power consumption. Loss of electrode arc can be predicted and countered by lowering the electrodes and decreasing the reactance of the variable reactors.Type: GrantFiled: February 8, 2001Date of Patent: August 5, 2003Assignees: Hatch Associates Ltd., Satcon Power Systems Canada Ltd.Inventors: Thomas Lai Wai Ma, Mohammad Sedighy, Brian Kenneth Perkins, Theodorus Anthonius Gerritsen, Janos Rajda
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Patent number: 6573691Abstract: Variable shunt and series connected reactors are used in a complimentary combination in an electric arc furnace to provide improved flicker control. A power control system for an time-varying AC load, such as an electric arc furnace, connected to an AC power supply line includes a first variable reactance intermediate the power supply line and the load, and a second variable reactance connected in parallel with the power supply line. A control system is provided for (i) monitoring load current and adjusting the first variable reactance in response to changes in the monitored load current; and (ii) monitoring reactive power draw by the load and adjusting the second variable reactance in response to changes in the monitored reactive power draw. The first variable reactance and second variable reactance are each primarily used to mitigate flicker at different times during the load operation.Type: GrantFiled: October 17, 2001Date of Patent: June 3, 2003Assignees: Hatch Associates Ltd., Satcon Power Systems Canada Ltd.Inventors: Thomas Lai Wai Ma, Brooke Armstrong Stratton
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Publication number: 20030076075Abstract: Variable shunt and series connected reactors are used in a complimentary combination in an electric arc furnace to provide improved flicker control. A power control system for an time-varying AC load, such as an electric arc furnace, connected to an AC power supply line includes a first variable reactance intermediate the power supply line and the load, and a second variable reactance connected in parallel with the power supply line. A control system is provided for (i) monitoring load current and adjusting the first variable reactance in response to changes in the monitored load current; and (ii) monitoring reactive power draw by the load and adjusting the second variable reactance in response to changes in the monitored reactive power draw. The first variable reactance and second variable reactance are each primarily used to mitigate flicker at different times during the load operation.Type: ApplicationFiled: October 17, 2001Publication date: April 24, 2003Inventors: Thomas Lai Wai Ma, Brooke Armstrong Stratton
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Patent number: 6519274Abstract: A power control system for an AC electric arc furnace. The control system includes variable reactors located intermediate a furnace power supply and arc electrodes that are height adjustable. The control system monitors operating characteristics of the furnace that are indicative of the active power consumption of the furnace and adjusts the variable reactors and the electrode height so as to minimize variations in the active power consumption. Loss of electrode arc can be predicted and countered by lowering the electrodes and decreasing the reactance of the variable reactors.Type: GrantFiled: February 8, 2001Date of Patent: February 11, 2003Assignees: Hatch Associates Ltd., Satcon Power Systems Canada Ltd.Inventors: Thomas Lai Wai Ma, Mohammad Sedighy, Brian Kenneth Perkins, Theodorus Anthonius Gerritsen, Janos Rajda
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Publication number: 20020136260Abstract: A power control system for an AC electric arc furnace. The control system includes variable reactors located intermediate a furnace power supply and arc electrodes that are height adjustable. The control system monitors operating characteristics of the furnace that are indicative of the active power consumption of the furnace and adjusts the variable reactors and the electrode height so as to minimize variations in the active power consumption.Type: ApplicationFiled: February 8, 2001Publication date: September 26, 2002Inventors: Thomas Lai Wai Ma, Mohammad Sedighy, Brian Kenneth Perkins, Theodorus Anthonius Gerritsen, Janos Rajda
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Patent number: 5867523Abstract: An improved return path for electric current through a conductive hearth of a direct current arc furnace is provided by pressing a ring of water cooled copper blocks into the periphery of a sidewall of the hearth of the furnace, the hearth having zones of conductive refractory providing an electrical path between the contents of the furnace of the copper blocks. The hearth is compressed by a tensioned peripheral band which may also support the blocks. The peripheral water cooled copper blocks may be divided into multiple groups, each group connected to one pole of a direct current power supply, the opposite pole of which is connected to a suspended electrode, permitting control of arc deflection.Type: GrantFiled: May 28, 1996Date of Patent: February 2, 1999Assignee: Hatch Associates Ltd.Inventors: Bert Orland Wasmund, Thomas Lai Wai Ma, Nils Walter Voermann