Patents by Inventor Friedrich Lenhard
Friedrich Lenhard has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 9804203Abstract: The current sensor arrangement according to the compensation principle has a primary conductor, designed to generate a primary magnetic field dependent on a current to be measured flowing through it, a first secondary winding, designed to generate a first secondary magnetic field dependent on a first compensation current flowing through said winding, a second secondary winding designed to generate a second secondary magnetic field dependent on a second compensation current flowing through said winding, a magnetic field sensor designed to generate a measurement signal that represents a magnetic field detected by it; a magnetic core of soft magnetic material designed and arranged to magnetically interconnect a primary conductor, a first seconding winding, a second secondary winding, and a magnetic field sensor; a first evaluation circuit, downstream from the magnetic field sensor and upstream from the first secondary winding, and a second evaluation circuit, upstream from the second secondary winding.Type: GrantFiled: April 22, 2014Date of Patent: October 31, 2017Assignee: VACUUMSCHMELZE GMBH & CO. KGInventor: Friedrich Lenhard
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Publication number: 20170248636Abstract: The current sensor arrangement according to the compensation principle has a primary conductor, designed to generate a primary magnetic field dependent on a current to be measured flowing through it, a first secondary winding, designed to generate a first secondary magnetic field dependent on a first compensation current flowing through said winding, a second secondary winding designed to generate a second secondary magnetic field dependent on a second compensation current flowing through said winding, a magnetic field sensor designed to generate a measurement signal that represents a magnetic field detected by it; a magnetic core of soft magnetic material designed and arranged to magnetically interconnect a primary conductor, a first seconding winding, a second secondary winding, and a magnetic field sensor; a first evaluation circuit; and a second evaluation circuit.Type: ApplicationFiled: May 11, 2017Publication date: August 31, 2017Inventor: Friedrich LENHARD
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Patent number: 8941373Abstract: A current sensor comprising a primary conductor for conducting a current that is to be measured, at least two magnetic field probes for measuring magnetic fields, and a magnetic core, which has a closed ring structure having three or more corners that encloses the primary conductor, wherein each magnetic field probe is arranged on the magnetic core or in recesses in the magnetic core.Type: GrantFiled: July 27, 2012Date of Patent: January 27, 2015Assignee: Vacuumschmelze GmbH & Co. KGInventors: Friedrich Lenhard, Sebastian Kudimow
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Publication number: 20140312892Abstract: The current sensor arrangement according to the compensation principle has a primary conductor, designed to generate a primary magnetic field dependent on a current to be measured flowing through it, a first secondary winding, designed to generate a first secondary magnetic field dependent on a first compensation current flowing through said winding, a second secondary winding designed to generate a second secondary magnetic field dependent on a second compensation current flowing through said winding, a magnetic field sensor designed to generate a measurement signal that represents a magnetic field detected by it; a magnetic core of soft magnetic material designed and arranged to magnetically interconnect a primary conductor, a first seconding winding, a second secondary winding, and a magnetic field sensor; a first evaluation circuit, downstream from the magnetic field sensor and upstream from the first secondary winding, and designed to generate a first compensation current corresponding to the measurementType: ApplicationFiled: April 22, 2014Publication date: October 23, 2014Applicant: Vaccumschmelze GmbH & Co. KGInventor: Friedrich LENHARD
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Publication number: 20130057272Abstract: Current sensor comprising a primary conductor for conducting a current that is to be measured, at least two magnetic field probes for measuring magnetic fields, and a magnetic core, which has a closed ring structure that encloses the primary conductor and at least two recesses that in each case receive one of the magnetic field probes.Type: ApplicationFiled: July 27, 2012Publication date: March 7, 2013Applicant: Vacuumschmelze GmbH & Co. KGInventors: Friedrich LENHARD, Sebastian KUDIMOW
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Publication number: 20130027024Abstract: A current sensor comprising a primary conductor for conducting a current that is to be measured, at least two magnetic field probes for measuring magnetic fields, and a magnetic core, which has a closed ring structure having three or more corners that encloses the primary conductor, wherein each magnetic field probe is arranged on the magnetic core or in recesses in the magnetic core.Type: ApplicationFiled: July 27, 2012Publication date: January 31, 2013Applicant: Vacuumschmelze GmbH & Co., KGInventors: Friedrich Lenhard, Sebastian Kudimow
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Publication number: 20130027033Abstract: Current sensor arrangement with a primary conductor for conducting a current that is to be measured, at least two magnetic field probes for measuring magnetic fields, and a magnetic core, which has a closed, arbitrarily formed ring structure that encloses the primary conductor, whereby a primary conductor guide for both rectangular and round primary conductors is located in a magnetic core opening that is enclosed by the magnetic core, and whereby the primary conductor guide has a solid body with a round guide opening that is arranged to overlap relative to the magnetic core opening and with a rectangular guide opening that extends over the round guide opening and that is arranged to overlap.Type: ApplicationFiled: July 27, 2012Publication date: January 31, 2013Applicant: Vacuumschmelze GmbH & Co. KGInventors: Friedrich LENHARD, Sebastian Kudimow
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Patent number: 7358716Abstract: A measuring method for measuring currents with a large dynamic range by means of a magnetic measuring module has the steps of switching into a high-current mode when a current threshold value is exceeded, and switching into a low-current mode otherwise, wherein the low-current mode has the following steps:—Feeding a first current pulse to a compensation coil, which drives a magnetic core in a first direction until magnetic saturation occurs,—measuring a first primary current value I1 after the current pulse is disconnected,—feeding a second current pulse to the compensation coil, which drives the magnetic core in a counter second direction until magnetic saturation occurs,—measuring a second primary current value I2 after the second current pulse is disconnected,—determining the corrected primary current value subsequently as an average value I=(I1+I2)/2 from the first and the second primary current values.Type: GrantFiled: January 12, 2006Date of Patent: April 15, 2008Assignee: Vacuumschmelze GmbH & Co. KGInventors: Norbert Preusse, Stefan Schaefer, Friedrich Lenhard
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Publication number: 20060158176Abstract: A measuring method for measuring currents with a large dynamic range by means of a magnetic measuring module has the steps of switching into a high-current mode when a current threshold value is exceeded, and switching into a low-current mode otherwise, wherein the low-current mode has the following steps:—Feeding a first current pulse to a compensation coil, which drives a magnetic core in a first direction until magnetic saturation occurs,—measuring a first primary current value I1 after the current pulse is disconnected,—feeding a second current pulse to the compensation coil, which drives the magnetic core in a counter second direction until magnetic saturation occurs,—measuring a second primary current value I2 after the second current pulse is disconnected,—determining the corrected primary current value subsequently as an average value I=(I1+I2)/2 from the first and the second primary current values.Type: ApplicationFiled: January 12, 2006Publication date: July 20, 2006Inventors: Norbert Preusse, Stefan Schaefer, Friedrich Lenhard
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Patent number: 7057485Abstract: Addressed is a current transformer comprising a primary conductor, a secondary winding and a soft-magnetic core, whereby the primary conductor and secondary winding are electrically insulated from one another and are magnetically intercoupled via the core. In addition, a current to be detected is injected into the primary conductor, and a compensating current is injected into the secondary winding. An additional conductor is provided which is electrically connected in parallel to the primary winding, and which is situated in the area of the core at which a flux rise occurs, whereby the flux rise is at least partially compensated for by the flux elicited by the current flowing in the additional conductor.Type: GrantFiled: March 5, 2001Date of Patent: June 6, 2006Assignee: Vacuumschmelze GmbH & Co. KGInventors: Norbert Preusse, Friedrich Lenhard, Stefan Schäfer
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Patent number: 6788046Abstract: The invention relates to a compensation current sensor, comprising a magnet core (M4), with a first section around which a secondary winding (S4) is wound. A magnetic field probe (MS4) is arranged in the vicinity of the secondary winding (S4). A primary winding is magnetically coupled with the secondary winding (S4). A metal screen (A4) is provided at a distance from the magnet core (M4). On the plane, on which the magnet core (M4) lies, the shield (A4) surrounds the magnet core (M4), with the exception of a side opening, whereby part of the opening is in the vicinity of the magnetic field probe (MS4) and arranged and configured such that magnetic flux which passes through the shield (A4), partially passes through the magnetic field probe (MS4).Type: GrantFiled: November 21, 2002Date of Patent: September 7, 2004Assignee: Vacuumschmelze GmbH & Co., KGInventors: Friedrich Lenhard, Stefan Schäfer
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Patent number: 6713999Abstract: A current sensor (1) is provided with low-pass filters (17 and 18) for stabilizing the pulse-duration modulated compensation signal. The current sensor is also provided with an additional RC element (40). Furthermore, a limiting means consisting of Zener diodes (44) and an ohmic resistance (45) is provided for suppressing fast current transients.Type: GrantFiled: February 15, 2002Date of Patent: March 30, 2004Assignees: Vacuumschmelze GmbH, Semikron Elektronik GmbHInventors: Friedrich Lenhard, Stefan Schäfer, Paul Mourick
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Publication number: 20030179063Abstract: The invention relates to a current transformer comprising a primary conductor, a secondary winding and a soft-magnetic core, whereby the primary conductor and secondary winding are electrically insulated from one another and are magnetically intercoupled via the core. In addition, a current to be detected is injected into the primary conductor, and a compensating current is injected into the secondary winding. According to the invention, an additional conductor is provided which is electrically connected in parallel to the primary winding, and which is situated in the area of the core at which a flux rise occurs, whereby the flux rise is at least partially compensated for by the flux elicited by the current flowing in the additional conductor.Type: ApplicationFiled: November 22, 2002Publication date: September 25, 2003Inventors: Norbert Preusse, Friedrich Lenhard, Stefan Schafer
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Publication number: 20030160601Abstract: The invention relates to a compensation current sensor, comprising a magnet core (M4), with a first section around which a secondary winding (S4) is wound. A magnetic field probe (MS4) is arranged the vicinity of the secondary winding (S4). A primary winding is magnetically coupled with the secondary winding (S4). A metal screen (A4) is provided at a distance from the magnet core (M4). On the plane, on which the magnet core (M4) lies, the shield (A4) surrounds the magnet core (M4), with the exception of a side opening, whereby part of the opening is in the vicinity of the magnetic field probe (MS4) and arranged and configured such that magnetic flux which passes through the shield (A4), partially passes through the magnetic field probe (MS4).Type: ApplicationFiled: November 21, 2002Publication date: August 28, 2003Inventors: Friedrich Lenhard, Stefan Schafer
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Patent number: 6388549Abstract: A magnet core for current sensors composed of a soft-magnetic alloy is disclosed which comprises at least two bent or buckled alloy band sections. A magnet core is also described with a primary leg and a secondary leg, whereby the secondary leg is formed of an alloy band section in single lay and of an alloy band section in double lay. The invention is also directed to a current sensor and to a method for manufacturing a magnet core.Type: GrantFiled: November 15, 1999Date of Patent: May 14, 2002Assignee: Vacuumschmelze GmbHInventor: Friedrich Lenhard
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Patent number: 6218825Abstract: Current sensor with a magnetic core (8) on which, besides a primary winding (9) in which the current to be measured (i) flows, at least one secondary winding (5) is wound, into which winding an alternating current that is generated by a generator circuit (1 to 7; 14 to 29) is fed, said current saturating the magnetic core (8) in alternating fashion in at least one direction, whereby the generator circuit is self-running, whereby the polarity of the alternating current generated by the generator circuit (1 to 7; 14 to 29) alternates depending on the current flowing in the secondary winding (5) and on at least one threshold value for this current.Type: GrantFiled: July 30, 1999Date of Patent: April 17, 2001Assignee: Vacuumschmelze GmbHInventor: Friedrich Lenhard
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Patent number: 6177791Abstract: Current sensor according to the compensation principle, in which the magnetic field produced by a primary winding (1) through which the current to be measured flows is compensated by the compensation current in a secondary winding (6), and in which for the controlling of the compensation current at least one sensor (3) that is influenced by the magnetic field acquires deviations from the zero current and supplies this measurement value to a driver circuit (5) for the production of the compensation current, whereby at the output of the driver circuit (5) the secondary winding (6) is connected in series to a terminating resistance (7), a voltage (Ua) that is proportional to the current to be measured is present at the terminating resistance (7), two amplifiers (5a,5b) in a bridge circuit, which are controlled by the measurement value and which supply output signals in phase opposition to one another, are used as a driver circuit (5), and the series circuit of the secondary winding (6) and terminating resistanceType: GrantFiled: July 30, 1999Date of Patent: January 23, 2001Assignee: Vacuumschmelze GmbHInventor: Friedrich Lenhard
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Patent number: 6078172Abstract: A current-compensated current sensor for hysteresis-dependent and temperature-dependent measurement of even relatively large currents at different frequencies, includes a soft-magnetic magnet core having a flat magnetization loop. The sensor thus also permits rapid changes in a primary current to be measured.Type: GrantFiled: May 6, 1997Date of Patent: June 20, 2000Assignee: Vacuumschmelze GmbHInventor: Friedrich Lenhard
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Patent number: 5565765Abstract: A current sensor operating according to the compensation thereon which is particularly suited for acquiring high currents has a secondary winding of the current transformer is divided into at least two sub-windings that are supplied by different amplifiers in an amplifier arrangement. This results in symmetrical loading of the supply voltage so that twice as high a compensation current is enabled given the same internal resistance of the sub-windings and same resistance of the terminating resistor as in known current sensors of this type.Type: GrantFiled: June 26, 1995Date of Patent: October 15, 1996Assignee: Vacuumschmelze GmbHInventor: Friedrich Lenhard