Electricity: electrical systems and devices – Control circuits for electromagnetic devices – Systems for magnetizing – demagnetizing – or controlling the...
Reexamination Certificate
2011-08-16
2011-08-16
Patel, Dharti H (Department: 2836)
Electricity: electrical systems and devices
Control circuits for electromagnetic devices
Systems for magnetizing, demagnetizing, or controlling the...
C361S143000, C361S152000
Reexamination Certificate
active
08000078
ABSTRACT:
A magnet controller supplied by an AC source controls a lifting magnet. Two bridges allow DC current to flow in both directions in the lifting magnet. During “Lift”, relatively high voltage is applied to the lifting magnet until it reaches its cold current. Then voltage is lowered. After a desired interval, once the magnet has had time to build its electromagnetic field, voltage is further reduced to prevent the magnet from overheating. The magnet lifting forced is maintained due to the magnetic circuit hysteresis. During “Drop”, reverse voltage is applied briefly to demagnetize the lifting magnet. At the end of the “Lift” and the “Drop”, most of the lifting magnet energy is returned to the line source. A logic controller controls current and voltage of the magnet and calculates the magnet's temperature. In one embodiment, a “Sweep” switch is provided to allow reduction of the magnet power to prevent attraction to the bottom or walls of magnetic rail cars or containers.
REFERENCES:
patent: 3445105 (1969-05-01), Marcher
patent: 3859571 (1975-01-01), Strobl et al.
patent: 5813712 (1998-09-01), Mozelt
patent: 5875281 (1999-02-01), Thexton et al.
patent: 5905624 (1999-05-01), Andreica et al.
patent: 6088210 (2000-07-01), Goodman
patent: 6710574 (2004-03-01), Davis et al.
patent: 7461569 (2008-12-01), Bianchi
patent: 7495879 (2009-02-01), Thexton et al.
patent: 7697253 (2010-04-01), Maraval
patent: 2005/0094345 (2005-05-01), Pollock et al.
patent: 2008/0143260 (2008-06-01), Tuymer et al.
patent: 2009/0160590 (2009-06-01), Maraval et al.
patent: 2920948 (2007-07-01), None
patent: 2610781 (1977-09-01), None
patent: 05343222 (1993-12-01), None
patent: 09142770 (1997-06-01), None
patent: 2002359112 (2002-12-01), None
patent: 2004299821 (2004-10-01), None
patent: WO 2009/086171 (2009-07-01), None
Fukada Takafumi, Method and apparatus for controlling voltage of lifting mgnet, Publication date: Dec. 13, 2002, par. 0004 and drawing 4.
International Search Report from PCT/US2008/087785, Apr. 6, 2009, 5 pages.
Notice of Allowance dated Dec. 2, 2009 from Related U.S. Appl. No. 11/757,304.
Knobbe Martens Olson & Bear LLP
Patel Dharti H
The Electric Controller & Manufacturing Company, LLC
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