Joel S Duga

6679076, Jan 20, 2004

Apr 17, 2003

10/419451

Joel S. Duga - Onalaska WI
John A. Komperud - La Crosse WI
Richard M. Heiden - Holmen WI

American Standard International Inc. - New York NY

F25B 4900

622281, 62498

A centrifugal chiller includes both a unit-mounted full-voltage starter and a unit-mounted reduced-voltage starter. The chiller is rather large with a rated cooling capacity of at least 300 tons and is driven by a motor that is powered by at least 2,000 volts. The chiller includes an evaporator shell and a condenser shell in a staggered arrangement to provide a combined height of between 6 and 12 feet and a combined width of between 5 and 8. 5 feet. The staggered arrangement of the shells plus mounting the two starters at opposite sides of the motor provide a chiller whose outer dimensions permit the chiller to be shipped as a single package without exceeding certain shipping limits.

7922467, Apr 12, 2011

Jan 5, 2007

11/650279

Robert M. Swanson - La Crosse WI, US
Joel S. Duga - Onalaska WI, US
David M. Foye - La Crosse WI, US

Trane International Inc - Piscataway NJ

F04D 17/08
F04D 29/056
F04D 29/60

4174237, 41742312, 41742314, 310 68 R, 310 71, 310 89, 310 90

To protect the bearings, lubricant and seals of a refrigerant compressor, the compressor includes one or more inductors for mitigating a high frequency common mode current that produces a high frequency shaft voltage. Each inductor is a ring of magnetic material encircling three insulated cables that convey three-phase power from an adjustable frequency drive to the compressor's motor. Without the inductors, the high frequency shaft voltage can become damagingly high due to the length of a cast iron housing that can be particularly long if the housing contains both a motor and several centrifugal impellers. The high frequency shaft voltage is just one component of a composite adverse shaft voltage. Another component, known as an operationally induced shaft voltage, can be reduced by a grounding contact, so instead of using just an inductor or just a contact, both can be used to provide a total solution to the problem.

20070201995, Aug 30, 2007

Feb 24, 2006

11/361329

Michael Harstad - Westby WI, US
Joel Duga - Onalaska WI, US
Gregory Fiegen - La Crescent MN, US
Brian Sullivan - La Crosse WI, US
James Kwiatkowski - Stoddard WI, US
Peter Kotlarek - Onalaska WI, US
Richard Heiden - Holmen WI, US

F04B 17/00

417423120

A refrigerant motor/compressor employs both a serviceable shaft-grounding device and a ceramic coating to protect a rolling element bearing that could otherwise be damaged by high frequency induced common mode voltage and current originating from an inverter that includes a plurality of IGBTs (insulate gate bipolar transistors). The shaft-grounding device includes a stranded copper wire brush that rides against an axial end of the shaft and a high frequency stranded grounding wire that conducts the induced current away from the shaft. The shaft-grounding device is sized and positioned so that it can be momentarily removed for inspection without having to evacuate the refrigerant. The ceramic coating provides an electrical insulating surface on a bearing bracket and other parts that support the bearing. The coating comprises titanium dioxide and aluminum oxide to provide a surface that is sufficiently hard and tough to resist damage during assembly, thereby maintaining the coating's integrity.

20110179644, Jul 28, 2011

Apr 4, 2011

13/065977

Robert M. Swanson - La Crosse WI, US
Joel S. Duga - Onalaska WI, US
David M. Foye - La Crosse WI, US

B23P 6/00

29888021

To protect the bearings, lubricant and seals of a refrigerant compressor, the compressor includes one or more inductors for mitigating a high frequency common mode current that produces a high frequency shaft voltage. Each inductor is a ring of magnetic material encircling three insulated cables that convey three-phase power from an adjustable frequency drive to the compressor's motor. Without the inductors, the high frequency shaft voltage can become damagingly high due to the length of a cast iron housing that can be particularly long if the housing contains both a motor and several centrifugal impellers. The high frequency shaft voltage is just one component of a composite adverse shaft voltage. Another component, known as an operationally induced shaft voltage, can be reduced by a grounding contact, so instead of using just an inductor or just a contact, both can be used to provide a total solution to the problem.

62440586, Jun 12, 2001

Jan 21, 2000

9/489203

Joel S. Duga - Onalaska WI
Steven J. Pitts - LaCrescent MN
John H. Roberts - La Crosse WI

American Standard International Inc. - New York NY

F25D 1700

62177

A tube and shell evaporator operable at near freezing includes a temperature sensor that senses the temperature of chilled water discharging from one or just a few of the very coldest tubes, whereby the sensed temperature is less than the average leaving chiller water temperature (LCWT). The result provides an exceptionally low LCWT, which can be especially desirable in district cooling systems where the chilled water is usually piped a great distance.

20150038016, Feb 5, 2015

Jul 31, 2014

14/448772

- Piscataway NJ, US
Joel S. Duga - Onalaska WI, US
Jon Christopher Johnson - New Albin IA, US

H01B 17/20
H01R 43/16
H01B 17/58
H01R 24/28
H01R 13/04

439625, 174212, 29874

A terminal assembly configured to conduct current from an external power source to a hermetical motor-compressor unit. The terminal assembly includes a terminal board, at least one opening defined through the thickness of the terminal board, at least a conductive pin received in the opening, and an insulator having a convoluted contour. The insulator may be disposed over the conductive pin and spaced away from the terminal board.