Patents by Inventor Charles F. Blair
Charles F. Blair 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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Method to reduce inrush currents in a transformer-less rectifier uninterruptible power supply system
Patent number: 10439431Abstract: A method reduces inrush currents in a transformer-less rectifier UPS system when an input circuit breaker of the UPS system is closed from an open position. The circuit breaker is coupled between an AC power input and an AC input of a rectifier of the UPS system and a DC output of the rectifier is coupled to a DC bus of the UPS system. Before the circuit breaker is closed, the DC bus is charged to a DC voltage having a level that is equal to a peak AC voltage level of a line-line AC voltage of AC input power to the UPS system. The rectifier is operated as an inverter to provide an AC output voltage at the AC input of the rectifier that is equal to an AC voltage at the AC power input and when it is equal, the circuit breaker is closed.Type: GrantFiled: January 23, 2017Date of Patent: October 8, 2019Assignee: Vertiv CorporationInventors: Charles F. Blair, Terry D. Bush, Xian Chen -
Patent number: 10404094Abstract: The present disclosure relates to a load sharing system having a plurality of power supplies for powering a plurality of corresponding loads. Each one of the power supplies is associated with at least one of the loads. A power bus is also provided. A plurality of inductors is connected to the power bus. Each one of the inductors is further connected to at least one of the loads and to at least one of the power supplies, such that each adjacent pair of the inductors is connected in parallel relative to at least one of the loads. Each of the inductors has an inductance value sufficient so that if a fault develops on the power bus it serves to isolate the power supplies from the power bus. The inductance value further is such that if any one of the power supplies fails, the specific pair of inductors coupled in parallel to the load associated with the failed power supply allows the load to draw power over the power bus from other ones of the power supplies through the specific pair of inductors.Type: GrantFiled: May 10, 2016Date of Patent: September 3, 2019Assignee: Vertiv CorporationInventors: Terry D. Bush, Charles F. Blair, Gregg J. Nelson
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Patent number: 10340733Abstract: A common mode choke in a 3-wire transformer free UPS system with which different rectifier and bypass power sources are used is eliminated by using different types of PWM control depending on whether the inverter is paralleled with the bypass power source. When the inverter is paralleled with the bypass power source, a type of PWM control is used that does not have common mode voltage injection. When the inverter is not paralleled with the bypass power source, a type of PWM control is used that has common mode voltage injection. In an aspect, the PWM control that does not have common mode voltage injection is sine-triangle PWM and the PWM control that has common mode voltage injection is space-vector PWM.Type: GrantFiled: February 6, 2015Date of Patent: July 2, 2019Assignee: Vertiv CorporationInventors: Edwin Shires, Terry D. Bush, Brian P. Heber, Charles F. Blair
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Patent number: 9915687Abstract: A real current meter reads current from a current probe coupled around power lines of a transformer-based UPS system coupled to a transformer having a high resistance ground with a HRG resistance and determines a real current component of the current read from the current probe.Type: GrantFiled: March 21, 2016Date of Patent: March 13, 2018Assignee: Liebert CorporationInventors: James K. Martin, Terry D. Bush, Charles F. Blair
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Method To Reduce Inrush Currents In A Transformer-Less Rectifier Uninterruptible Power Supply System
Publication number: 20170244277Abstract: A method reduces inrush currents in a transformer-less rectifier UPS system when an input circuit breaker of the UPS system is closed from an open position. The circuit breaker is coupled between an AC power input and an AC input of a rectifier of the UPS system and a DC output of the rectifier is coupled to a DC bus of the UPS system. Before the circuit breaker is closed, the DC bus is charged to a DC voltage having a level that is equal to a peak AC voltage level of a line-line AC voltage of AC input power to the UPS system. The rectifier is operated as an inverter to provide an AC output voltage at the AC input of the rectifier that is equal to an AC voltage at the AC power input and when it is equal, the circuit breaker is closed.Type: ApplicationFiled: January 23, 2017Publication date: August 24, 2017Applicant: Liebert CorporationInventors: Charles F. BLAIR, Terry D. BUSH, Xian CHEN -
Publication number: 20160336796Abstract: The present disclosure relates to a load sharing system having a plurality of power supplies for powering a plurality of corresponding loads. Each one of the power supplies is associated with at least one of the loads. A power bus is also provided. A plurality of inductors is connected to the power bus. Each one of the inductors is further connected to at least one of the loads and to at least one of the power supplies, such that each adjacent pair of the inductors is connected in parallel relative to at least one of the loads. Each of the inductors has an inductance value sufficient so that if a fault develops on the power bus it serves to isolate the power supplies from the power bus. The inductance value further is such that if any one of the power supplies fails, the specific pair of inductors coupled in parallel to the load associated with the failed power supply allows the load to draw power over the power bus from other ones of the power supplies through the specific pair of inductors.Type: ApplicationFiled: May 10, 2016Publication date: November 17, 2016Inventors: Terry D. BUSH, Charles F. BLAIR, Gregg J. NELSON
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Publication number: 20160282390Abstract: A real current meter reads current from a current probe coupled around power lines of a transformer-based UPS system coupled to a transformer having a high resistance ground with a HRG resistance and determines a real current component of the current read from the current probe.Type: ApplicationFiled: March 21, 2016Publication date: September 29, 2016Inventors: James K. MARTIN, Terry D. BUSH, Charles F. BLAIR
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Publication number: 20160094209Abstract: A DC offset voltage in an AC input voltage to a transformer and associated saturation current are eliminated by the placement of an anti-parallel diode pair circuit in series between a source of the AC input voltage and a primary winding of the transformer. The anti-parallel diode pair circuit has an input coupled to an output by parallel connected oppositely biased branch diode circuits. Each branch diode circuit has at least one diode where the diode of one such branch diode circuit is biased in one direction and the diode of the other such branch diode circuit is biased in an opposite direction and each branch diode circuit has the same number of diodes as the other branch diode circuit.Type: ApplicationFiled: September 11, 2015Publication date: March 31, 2016Applicant: LIEBERT CORPORATIONInventors: Terry D. BUSH, Charles DUNN, James MILLER, Charles F. BLAIR
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Publication number: 20150244206Abstract: A common mode choke in a 3-wire transformer free UPS system with which different rectifier and bypass power sources are used is eliminated by using different types of PWM control depending on whether the inverter is paralleled with the bypass power source. When the inverter is paralleled with the bypass power source, a type of PWM control is used that does not have common mode voltage injection. When the inverter is not paralleled with the bypass power source, a type of PWM control is used that has common mode voltage injection. In an aspect, the PWM control that does not have common mode voltage injection is sine-triangle PWM and the PWM control that has common mode voltage injection is space-vector PWM.Type: ApplicationFiled: February 6, 2015Publication date: August 27, 2015Applicant: LIEBERT CORPORATIONInventors: Edwin SHIRES, Terry D. BUSH, Brian P. HEBER, Charles F. BLAIR
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Patent number: 7453235Abstract: A modular uninterruptible power supply is disclosed, which provides complete redundancy for all components required for UPS operation. Novel aspects of the invention include design of the modules and their interconnection and interoperability, as well as improved operation techniques applicable to UPS systems generally.Type: GrantFiled: February 11, 2004Date of Patent: November 18, 2008Assignee: Liebert CorporationInventors: Charles F Blair, Mark Gabel, Christopher Crawford, Dennis Weber, John R Birchmeier, Brad Reinbolt
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Publication number: 20040160214Abstract: A modular uninterruptible power supply is disclosed, which provides complete redundancy for all components required for UPS operation. Novel aspects of the invention include design of the modules and their interconnection and interoperability, as well as improved operation techniques applicable to UPS systems generally.Type: ApplicationFiled: February 11, 2004Publication date: August 19, 2004Applicant: LIEBERT CORPORATIONInventors: Charles F. Blair, Mark Gabel, Christopher Crawford, Dennis Weber, John R. Birchmeier, Brad Reinbolt
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Patent number: 6700351Abstract: A modular uninterruptible power supply is disclosed, which provides complete redundancy for all components required for UPS operation. Novel aspects of the invention include design of the modules and their interconnection and interoperability, as well as improved operation techniques applicable to UPS systems generally.Type: GrantFiled: February 20, 2001Date of Patent: March 2, 2004Assignee: Liebert CorporationInventors: Charles F. Blair, Mark Gabel, Christopher Crawford, Dennis Weber, John R. Birchmeier, Brad Reinbolt
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Publication number: 20010033502Abstract: A modular uninterruptible power supply is disclosed, which provides complete redundancy for all components required for UPS operation. Novel aspects of the invention include design of the modules and their interconnection and interoperability, as well as improved operation techniques applicable to UPS systems generally.Type: ApplicationFiled: February 20, 2001Publication date: October 25, 2001Inventors: Charles F. Blair, Mark Gabel, Christopher Crawford, Dennis Weber, John R. Birchmeier, Brad Reinbolt