| Patent Number |
Title Of Patent |
Date Issued |
| 8014110 |
Variable speed drive with integral bypass contactor |
September 6, 2011 |
| Systems and methods for operating a variable speed drive to receive an input AC power at a fixed AC input voltage and frequency and provide an output AC power at a variable voltage and variable frequency. The variable speed drive includes a converter stage to convert the input AC vol |
| 8004803 |
Variable speed drive |
August 23, 2011 |
| Systems and methods for improved Variable Speed Drives are provided. One embodiment relates to apparatus for common mode and differential mode filtering for motor or compressor bearing protection when operating with Variable Speed Drives, including conducted EMI/RFI input power mains |
| 7957166 |
Variable speed drive |
June 7, 2011 |
| Systems and methods for improved Variable Speed Drives are provided. One embodiment relates to apparatus for common mode and differential mode filtering for motor or compressor bearing protection when operating with Variable Speed Drives, including conducted EMI/RFI input power mains |
| 7876561 |
Cooling systems for variable speed drives and inductors |
January 25, 2011 |
| A plastic liquid cooled variable speed drive or inductor provided. The cooler provides lightweight, space conservative, corrosive free cooling to the components as well as provides a mounting area for modules. A cooler can be mounted to the core of an inductor to absorb heat generated |
| 7764041 |
System and method to extend synchronous operation of an active converter in a variable speed dri |
July 27, 2010 |
| Systems and methods for synchronous operation of variable speed drives having active converters include extending the synchronous operation of an active converter to the AC mains voltage during complete line dropout. A phase angle control circuit includes a squaring amplifier, a first |
| 7746020 |
Common mode & differential mode filter for variable speed drive |
June 29, 2010 |
| Systems and methods for improved Variable Speed Drives having active inverters include an input filter for filtering common mode and differential mode currents. A three-phase inductor has three windings, each winding of the three-phase inductor having a center tap dividing each windi |
| 7640767 |
Low voltage variable speed drive for application on medium/high voltage mains |
January 5, 2010 |
| The present invention is directed to a power transformer and VSD mounted on the chiller equipment. The transformer is preferably a liquid-filled transformer rated for medium/high voltage input, and at least two output low voltages, one voltage for the VSD and other power equipment, and |
| 7619906 |
System for precharging a DC link in a variable speed drive |
November 17, 2009 |
| A variable speed drive with a converter that is controllable to precharge a DC link is provided. The variable speed drive also includes an inverter. The converter converts a fixed line frequency, fixed line voltage AC power from an AC power source into DC power. The DC link filters t |
| 7332885 |
Ride-through method and system for HVAC&R chillers |
February 19, 2008 |
| A method of providing ride-through capability in a chiller/refrigeration system employs a variable speed drive with an active converter stage, a DC link stage and an inverter stage for providing variable frequency and voltage to power at least one motor. An induction motor is coupled to |
| 6434003 |
Liquid-cooled power semiconductor device heatsink |
August 13, 2002 |
| The present invention relates to a cold plate for cooling electronic components comprising a base having a top surface onto which at least one electronic component is to be placed; a cooling well formed in the top of the base and open at the top; a feed channel formed in the base for |
| 6404346 |
Method and apparatus for detecting a failed thyristor |
June 11, 2002 |
| A method or system consistent with this invention for detecting if a thyristor failed open in an alternating current input phase of a load comprises measuring an instantaneous power delivered to the load during a cycle of the input; determining a peak power delivered to the load during |
| 6404265 |
Highly efficient driver circuit for a solid state switch |
June 11, 2002 |
| Systems consistent with this invention comprise a trigger circuit for triggering a silicon device having a control terminal, where the silicon device is subject to variations in the intrinsic control requirements. The trigger circuit comprises a source of direct current (DC) supply volta |
| 6339352 |
Anticipatory Schmitt trigger |
January 15, 2002 |
| A system and method for providing an anticipatory Schmitt trigger circuit that changes the output level of the trigger circuit in anticipation of crossing a predetermined voltage value such as a zero voltage level. In an exemplary embodiment, the anticipatory Schmitt trigger includes a |
| 6211792 |
Method and apparatus detecting a failed thyristor |
April 3, 2001 |
| Methods and systems consistent with this invention detect a failed short thyristor in a solid-state controller for delivering power to a load during reduced-voltage operation. Methods and systems consistent with this invention detect a voltage across the thyristor, and indicate a failed |
| 5923143 |
Solid state motor starter with energy recovery |
July 13, 1999 |
| A motor starter circuit providing recovery of the energy trapped in the motor windings when the supply voltage and current have opposite polarities by selectively controlling actuation of a plurality of high speed switches. The circuit, for use with a multiphase motor and power sourc |
| 5898554 |
Switch driver circuit |
April 27, 1999 |
| A driver circuit for a semiconductor power switch. The driver circuit supplies a high voltage pulse to the gate of an IGBT. The driver circuit also monitors the voltage on the collector of the IGBT with respect to the emitter. If the voltage at the collector of the IGBT does not drop whe |
| 5894736 |
Methods and apparatuses for detecting surge in centrifugal compressors |
April 20, 1999 |
| A surge detection system for use in a fluid system having a load driven by a centrifugal compressor, the compressor being driven by an electric motor. The surge detection system comprises a means for sensing a differential pressure developed across the compressor and a means for sens |
| 5850160 |
Gate drive circuit for an SCR |
December 15, 1998 |
| A gate drive circuit for a silicon controlled rectifier (SCR) connected in an a-c power circuit includes a voltage divider network connected between a d-c voltage source and the SCR for developing a varying voltage on a control node, depending upon whether the anode-to-cathode a-c voltag |
| 5838144 |
Solid state, reduced voltage motor starter enabling equalized input/output volt-amp ratings |
November 17, 1998 |
| A motor starter circuit for minimizing the amount of current drawn by the motor from a power source during starting of the motor through current transformation achieved by selectively controlling actuation of a plurality of high speed switches. The circuit is for use with a alternati |
| 5746062 |
Methods and apparatuses for detecting surge in centrifugal compressors |
May 5, 1998 |
| A surge detection system for use in a fluid system having a load driven by a centrifugal compressor, the compressor being driven by an electric motor. The surge detection system comprises a means for sensing a differential pressure developed across the compressor and a means for sens |
