1
Frederick A Stich, Thomas G Hubert, David L Layden, Donald K Zahrte: Uninterruptible power system. Best Power Technology Incorporated, Foley & Lardner, February 11, 1997: US05602462 (281 worldwide citation)

An uninterruptible power system has a transformer with a primary connected to input terminals, a secondary connected to output terminals, a static switch connected between the input terminals and the primary, and an auxiliary primary connected to an inverter which is supplied by a battery to provide ...


2
Frederick A Stich, Donald K Zahrte Sr, Richard V Baxter Jr, Douglas C Folts, Thomas G Hubert, Juan M Medina, William J Hazen, Edward G Beistle: Back-up uninterruptible power system. Best Power Technology, Foley & Lardner, May 24, 1994: US05315533 (150 worldwide citation)

A back-up uninterruptible power system has a power supply path from input terminals connected to AC power system lines to normally supply power to a load. Upon the occurrence of a line fault, a static switch in the power supply path interrupts the connection between the AC power lines and the load a ...


3
Craig Edevold, Cary Winch, Donald K Zahrte Sr, Joseph R Wade, Peter Jungwirth, Derek Laufenberg: Distributed internal fault bypass in a modular uninterruptible power supply. Powerware Corporation, Leydig Voit & Mayer, September 18, 2001: US06292379 (92 worldwide citation)

A modular uninterruptible power supply is presented having multiple power modules installed therein. Each of the individual power modules contains an internal bypass circuit sized for its particular power module. Preferably internal bypass circuitry is sized to carry two per unit load. The system an ...


4
Frederick A Stich, Peter W Jungwirth, Donald K Zahrte Sr: Standby power system. General Signal Corporation, Foley & Lardner, August 4, 1998: US05790391 (88 worldwide citation)

A standby power system is provided having power conversion, output voltage control, and line-fault detection systems that make possible a significant reduction in the cost of the system. The standby power system provides backup power to a load, such as a computer system, when main AC line power fail ...


5
Donald K Zahrte Sr, Peter Jungwirth: Uninterruptible power supply and ferroresonant transformer for use therewith. Powerware Corporation, Leydig Voit & Mayer, April 17, 2001: US06218744 (31 worldwide citation)

A line-interactive single conversion uninterruptible power supply (UPS) utilizing a multiple tapped ferroresonant transformer and a square wave PWM inverter is presented. During normal utility line operation, the line voltage is not modified in any way, except for ferroresonant filtering and regulat ...


6
Frederick A Stich, Donald K Zahrte Sr, Gregory C Kohls, Robert R Davidson: Dynamic voltage regulation stabilization for AC power supply systems. General Signal Corporation, Foley & Lardner, March 17, 1998: US05729120 (30 worldwide citation)

Instabilities in the output voltage provided from an AC power supply system such as an uninterruptible power supply connected to a power factor correcting load are suppressed by a dynamic voltage regulation stabilizer system which is connected across the output lines from the power supply system to ...


7
Donald K Zahrte Sr, David L Layden, Frederick A Stich, Douglas C Folts: Inverter having center switch and uninterruptible power supply implementing same. Powerware Corporation, Leydig Voit & Mayer, July 24, 2001: US06266260 (22 worldwide citation)

Presented is a center switching circuit and an inverter and an uninterruptible power supply (UPS) utilizing same. The center switching circuit selectively enables and disables power flow to and from the bus capacitors of an inverter or UPS. As such, the center switching circuitry effectively removes ...


8
Joseph R Wade, Glenn A Koosmann, Donald K Zahrte Sr: Battery charger control circuit and an uninterruptible power supply utilizing same. Powerware Corporation, Leydig Voit & Mayer, August 12, 2003: US06605879 (20 worldwide citation)

A charging control circuit for severe battery conditions and an uninterruptible power supply (UPS) system including same are presented. The charging control circuit utilizes both hardware and microprocessor control to allow the UPS to start with depleted or no batteries installed. Initially, the har ...


9
Mark R Swanson, William C Apperson, Donald K Zahrte Sr: Device and method for inspecting markings. Renaissance Learning, Merchant & Gould P C, June 27, 2006: US07068861 (3 worldwide citation)

A device and method for reading optical marks are disclosed. The device, an optical mark reader (OMR) has an array of photo sensors with light-emitting diodes (LEDs), which are driven by digital-to-analog converters (DACs), which are in turn controlled by a microcontroller. When calibrating the OMR, ...


10
Joseph R Wade, Glenn A Koosmann, Donald K Zahrte: Battery charger control circuit and an uninterruptible power supply utilizing same. Powerware Corporation, Leydig Voit & Mayer, October 24, 2002: US20020153779-A1

A charging control circuit for severe battery conditions and an uninterruptible power supply (UPS) system including same are presented. The charging control circuit utilizes both hardware and microprocessor control to allow the UPS to start with depleted or no batteries installed. Initially, the har ...