STEPHEN PATRICK BENESH
Pilots at Oak Crst Dr, Oshkosh, WI

License number

Wisconsin A2241021

Issued Date

Sep 2015

Expiration Date

Sep 2017

Professional information

Account Manager At Ge

Location:

Oshkosh, Wisconsin Area

Industry:

Electrical/Electronic Manufacturing

System For Monitoring A Dual Voltage Ungrounded System For Leakage Currents

US Patent:

5514964, May 7, 1996

Filed:

Aug 17, 1994

Appl. No.:

8/292121

Inventors:

Stephen P. Benesh - Oshkosh WI
David W. Hasenohrl - Oshkosh WI

Assignee:

Square D Company - Palatine IL

International Classification:

G01R 3114

US Classification:

324509

Abstract:

A system contained on a single isolation panel determines the hazard current of a dual voltage, ungrounded, polyphase system. The system uses a single isolation transformer having dual secondary windings for generating the dual voltages. A first line isolation monitor or LIM, is microcontroller based and continuously measures the fault impedance of one of the output voltages of the polyphase, ungrounded or isolated system. A second LIM continuously measures the fault impedance of the other output voltage of the system. The fault impedance is determined by the LIM by injecting a continuous sine wave measurement current into a ground terminal to generate a measurement voltage across the fault impedance. Using the measurement voltage and current, the LIM calculates the fault impedance and, using this impedance, calculates the hazard current based on the maximum line to ground voltage of the ungrounded system. The hazard current is displayed and if it exceeds a predetermined threshold, the LIM will provide audio and visual alarms.