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公开(公告)号：US20190190253A1
公开(公告)日：2019-06-20
申请号：US15848552
申请日：2017-12-20
发明人： Kevin M. JEFFERIES , Benjamin W. EDWARDS , Matthew L. WHITE , Alan E. FREEMAN , Richard K. WEILER
IPC分类号： H02H7/08
摘要： In accordance with an example embodiment of the invention, in an overload relay for a three-phase motor, an adjusted threshold for detected current phase unbalance is dynamically determined at which the relay will be tripped. The adjusted threshold is a function of a ratio of an average of currents in the three-phases to the rated full load current of the motor, i.e., motor load. As the motor load decreases, the adjusted current phase unbalance threshold is increased, causing the resulting trip time to increase, thereby increasing motor run time and reducing downtime.
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公开(公告)号：US20210119441A1
公开(公告)日：2021-04-22
申请号：US16654205
申请日：2019-10-16
发明人： Kevin M. JEFFERIES , Benjamin W. EDWARDS , Matthew L. WHITE , Alan E. FREEMAN , Richard K. WEILER
摘要： A progressive protection method automatically adapts a protection trip delay or fault timeout for a motor that is a member of a group of motors performing mutually similar or related tasks, based on the occurrence of a fault in another motor within the group, without requiring manual intervention. If the user requires stringent protection of the motors in a particular application, then the trip delay time for all of the motors in the group, may be shortened in response to recently-detected similar trips of other motors within the group. Alternatively, if the user prefers continuity of service for a particular application, then the trip delay time for all of the motors in the group, may be increased in response to recently-detected similar trips of other motors within the group, based on past experience with the occurrence of fault self-clearing for the motors in the group.
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公开(公告)号：US20190195922A1
公开(公告)日：2019-06-27
申请号：US15850988
申请日：2017-12-21
CPC分类号： G01R19/2506 , G01R15/18 , G01R19/2513 , G01R23/02
摘要： A system and method are provided to perform current sensor error compensation. The system and method involve obtaining a current measurement of a current on a circuit from a current sensor; obtaining a voltage measurement of a voltage associated with the current from a voltage sensor; determining a fundamental frequency of the voltage from the voltage measurement; and performing error compensation on the current measurement based on the determined fundamental frequency to produce a corrected current measurement. The current sensor error compensation may be performed to correct current measurements in a motor system, such as in a motor overload relay, at a low cost by using functionality already available in the system.
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公开(公告)号：US20220399837A1
公开(公告)日：2022-12-15
申请号：US17892432
申请日：2022-08-22
发明人： Kevin M. JEFFERIES , Benjamin W. EDWARDS , Alan E. FREEMAN , Richard K WEILER , Matthew L. WHITE
IPC分类号： H02P1/26
摘要： Techniques for monitoring the health of a three-phase induction motor are provided. An expected threshold value is calculated as a function of an expected ratio of current unbalance to voltage unbalance for the three-phase motor. Embodiments determine whether a measured current unbalance exceeds the expected threshold value. Responsive to the measured current unbalance exceeding the expected threshold value, a remedial action may be taken, such as generating diagnostic information or activating one or more protection operations for the three-phase induction motor.
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公开(公告)号：US20210181243A1
公开(公告)日：2021-06-17
申请号：US16715573
申请日：2019-12-16
IPC分类号： G01R19/25
摘要： A measurement module uses harmonic compensation factors to minimize the effects of harmonic distortion in measurements of a source current by a current sensor of the module. The module samples at a first sampling rate, measurements of the source current to generate a first current measurement. The module samples at a second sampling rate higher than the first sampling rate, for an interval of time, measurements of the source current to generate a second current measurement. The module determines a harmonic compensation factor based, at least, on a difference between the first current measurement and the second current measurement. The module determines a reported current computed as a function of at least the first current measurement, the difference between the first current measurement and the second current measurement, and the harmonic compensation factor. The reported current represents a magnitude of the source current adjusted by the harmonic compensation factor.
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公开(公告)号：US20210247429A1
公开(公告)日：2021-08-12
申请号：US16787278
申请日：2020-02-11
发明人： Kevin M. JEFFERIES , Matthew L. WHITE , Benjamin W. EDWARDS , Richard K. WEILER , Alan E. FREEMAN
摘要： A measurement module receives a defined system topology and system component characteristics information for a system. The measurement module calculates an expected system impedance for the defined system topology. The measurement module collects one or more impedance measurements using a high frequency voltage stimulus. Finally, the measurement module compares the one or more impedance measurements with the expected system impedance to determine adequacy of protective grounding of the system.
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公开(公告)号：US20190190428A1
公开(公告)日：2019-06-20
申请号：US15848758
申请日：2017-12-20
发明人： Richard K. WEILER , Benjamin W. Edwards , Alan E. FREEMAN , Kevin M. JEFFERIES , Julius M. LIPTAK , Matthew L. WHITE
IPC分类号： H02P23/26 , G05F1/70 , G01R31/02 , G01R31/327
CPC分类号： H02P23/26 , G01R31/028 , G01R31/3274 , G05F1/70
摘要： A system and method is provided to monitor wear on a power factor correction capacitor in a motor system. The system and method obtains a baseline inductance angle, reactive power or power factor corresponding to a baseline power factor correction by the capacitor in the circuit; monitors a current supplied to the motor at a location upstream of the capacitor; monitors a voltage supplied to the motor, and determines a present inductance angle, reactive power or power factor based on the monitored current and voltage. The present inductance angle, reactive power or power factor corresponds to a present power factor correction by the capacitor. The system and method can then determine when the power factor correction of the capacitor has degraded to an unsatisfactory level based on a change in the inductance angle, reactive power or power factor from the baseline values, and take appropriate action
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