Process for offset adjustment of a microprocessor based overcurrent protective device and apparatus

• US 5,251,157 A
• Filed: 12/28/1990
• Issued: 10/05/1993
• Est. Priority Date: 12/28/1990
• Status: Expired due to Term

• Current Assignee: Westinghouse Electric UK Holdings Limited (Fluor Corporation)
• Original Assignee: Westinghouse Electric Corporation (Paramount Global (f/k/a ViacomCBS Inc.))
• Inventors: Prather, Edward C.
• Primary Examiner(s): Teska, Kevin J.
• Application Number:
  US07/636,870
• Time in Patent Office: 1,012 Days
• Field of Search: 364/571.01-571.08, 364/481, 364/483, 364/492, 371/15.1, 371/16.4
• US Class Current: 702/105
• CPC Class Codes: H02H 3/006 Calibration or setting of parameters

Abstract

Process and apparatus for calibrating an electrical device such as a circuit breaker, motor controller or monitor is taught. A precision power supply device is interconnected by way of appropriate input channels to the device to be calibrated for supplying a precise accurate calibration variable as an input. A personal computer is interlinked by way of a communications network with the apparatus to be calibrated and is also interlinked with the precision supply device so that the personal computer has available the exact value of input variable utilized.

Claims

1. An electrical contactor that acts in the presence of a predetermined value of an input, electrical variable at an input thereto to perform a function, where an offset coefficient and a calibration factor are digitally stored in a memory region of said contactor and where any input electrical value within a range of input electrical values provides a corresponding derived electrical value in said contactor, comprising:

supply means for supplying a first value of said input electrical variable to said input where said first value is zero;

sensing means for sensing said supplied input electrical variable and producing a corresponding first derived value related thereto;

computing means having said first value of input electrical variable available thereto;

first communicating means for communicating said first derived value to said computing means;

said computing means calculating an offset coefficient within said computing means according to the relationship;

said offset coefficient equals said first derived value;

second communicating means for communicating said offset coefficient to said memory region for digital placement therein;

means for using said offset coefficient by said contactor in performing said function;

said supply supplying a second value of said input electrical variable to said input;

said sensing means sensing said supplied second input electrical variable and producing a corresponding second derived value related thereto;

said first communicating means communicating said second derived value to said computing means which also has said second value of input electrical variable available thereto;

said computing means calculating a calibration factor within said computing means according to the relationship;

said calibration factor is related to said second value of input electrical variable and said second derived value;

said second communicating means communicating said calibration factor to said memory region for digital placement therein; and

means for using said calibration factor by said contactor in performing said function.

2. A process for calculating an offset coefficient and a digital calibration factor for an electrical contactor that acts in the presence of a predetermined value of an input electrical variable at an input of said electrical contactor to perform a function, where said offset coefficient and said calibration factor are digitally stored in a memory region of said electrical contactor and where any input electrical value within a range of input electrical values provides a corresponding derived electrical value in said contactor, comprising the steps of:

supplying a first value of said input electrical variable to said input where said first value is zero;

sensing said supplied input electrical variable and producing in said electrical contactor a corresponding first derived value related thereto;

communicating said first derived value to a computing means;

calculating an offset coefficient within said computing means according to the relationship;

said offset coefficient equals said first derived value;

communicating said offset coefficient to said memory region for digital placement therein and subsequent use by said electrical contactor in performing said function;

supplying a second value of said input electrical variable to said input;

sensing said supplied second input electrical variable and producing in said electrical contactor a corresponding second derived value related thereto;

communicating said second derived value to said computing means which also has said second value of input electrical variable available thereto;

calculating a calibration factor within said computing means according to the relationship;

said calibration factor is related to said second value of input electrical variable and said second derived value; and

communicating said calibration factor to said offset coefficient memory region for digital placement therein and subsequent use by said electrical contactor in performing said function.

3. A monitor which acts in the presence of a predetermined value of an input electrical variable at an input thereto to perform a monitoring function, where an offset coefficient and a calibration factor are digitally stored in a memory region of said monitor and where any input electrical value within a range of input electrical values provides a corresponding derived electrical value in said monitor, comprising:

supply means for supplying a first value of said input electrical variable to said input where said first value is zero;

sensing means for sensing said supplied input electrical variable and producing a corresponding first derived value related thereto;

computing means having said first value of input electrical variable available thereto;

first communicating means for communicating said first derived value to said computing means;

said computing means calculating an offset coefficient within said computing means according to the relationship;

said offset coefficient equals said first derived value;

second communicating means for communicating said offset coefficient to said memory region for digital placement therein;

means for using said offset coefficient by said monitor in performing said function;

said supply supplying a second value of said input electrical variable to said input;

said sensing means sensing said supplied second input electrical variable and producing a corresponding second derived value related thereto;

said first communicating means communicating said second derived value to said computing means which also has said second value of input electrical variable available thereto;

said computing means calculating a calibration factor within said computing means according to the relationship;

said calibration factor is related to said second value of input electrical variable and said second derived value;

said second communicating means communicating said calibration factor to said memory region for digital placement therein; and

means for using said calibration factor by said monitor in performing said monitoring function.

4. A circuit breaker which acts in the presence of a predetermined value of an input electrical variable at an input thereto to perform a circuit protective function, where an offset coefficient and a calibration factor are digitally stored in a memory region of said circuit breaker and where any input electrical value within a range of input electrical values provides a corresponding derived electrical value in said circuit breaker, comprising:

supply means for supplying a first value of said input electrical variable to said input where said first value is zero;

sensing means for sensing said supplied input electrical variable and producing a corresponding first derived value related thereto;

computing means having said first value of input electrical variable available thereto;

first communicating means for communicating said first derived value to said computing means;

said computing means calculating an offset coefficient within said computing means according to the relationship;

said offset coefficient equals said first derived value;

second communicating means for communicating said offset coefficient to said memory region for digital placement therein;

means for using said offset coefficient by said circuit breaker in performing said function;

said supply supplying a second value of said input electrical variable to said input;

said sensing means sensing said supplied second input electrical variable and producing a corresponding second derived value related thereto;

said first communicating means communicating said second derived value to said computing means which also has second value of input electrical variable available thereto;

said computing means calculating a calibration factor within said computing means according to the relationship;

said calibration factor is related to said second value of input electrical variable and said second derived value;

said second communicating means communicating said calibration factor to said memory region for digital placement therein; and

means for using said calibration factor by said circuit breaker in performing said circuit protective function.

5. A circuit breaker which acts in the presence of a predetermined value of an input electrical variable at an input thereof to perform a circuit protective function, where an offset coefficient is digitally stored in an offset coefficient memory region of said circuit breaker and where any input electrical value within a range of input electrical values provides a corresponding derived electrical value in said circuit breaker, comprising:

supply means for supplying a first value of said input electrical variable to said input wherein said first value is zero;

sensing means for sensing said supplied input electrical variable and producing a corresponding first derived value related thereto, said first derived value being said offset coefficient;

communicating means for communicating said offset coefficient to said offset coefficient memory region for digital placement therein; and

means for using said offset coefficient by said circuit breaker in performing said circuit protective function.

6. A motor controller which acts in the presence of a predetermined value of an input electrical variable at an input thereto to perform a motor control function, where an offset coefficient and a calibration factor are digitally stored in a memory region of said motor controller and where any input electrical value within a range of input electrical values provides a corresponding derived electrical value in said motor controller, comprising:

supply means for supplying a first value of said input electrical variable to said input where said first value is zero;

sensing means for sensing said supplied input electrical variable and producing a corresponding first derived value related thereto;

computing means having said first value of input electrical variable available thereto;

first communicating means for communicating said first derived value to said computing means;

said computing means calculating an offset coefficient within said computing means according to the relationship;

said offset coefficient equals said first derived value;

second communicating means for communicating said offset coefficient to said memory region for digital placement therein;

means for using said offset coefficient by said motor controller in performing said function;

said supply supplying a second value of said input electrical variable to said input;

said sensing means sensing said supplied second input electrical variable and producing a corresponding second derived value related thereto;

said first communicating means communicating said second derived value to said computing means which also has said second value of input electrical variable available thereto;

said computing means calculating a calibration factor within said computing means according to the relationship;

said calibration factor is related to said second value of input electrical variable and said second derived value;

said second communicating means communicating said calibration factor to said memory region for digital placement therein; and

means for using said calibration factor by said motor controller in performing said motor control function.

7. A process for calculating an offset coefficient and a digital calibration factor for a monitor that acts in the presence of a predetermined value of an input electrical variable at an input of said monitor to perform a function, where said offset coefficient and said calibration factor are digitally stored in a memory region of said monitor and where any input electrical value within a range of input electrical values provides a corresponding derived electrical value in said monitor, comprising the steps of:

supplying a first value of said input electrical variable to said input where said first value is zero;

sensing said supplied input electrical variable and producing in said monitor a corresponding first derived value related thereto;

communicating said first derived value to a computing means;

calculating an offset coefficient within said computing means according to the relationship;

said offset coefficient equals said first derived value;

communicating said offset coefficient to said memory region for digital placement therein and subsequent use by said monitor in performing said function;

supplying a second value of said input electrical variable to said input;

sensing said supplied second input electrical variable and producing in said monitor a corresponding second derived value related thereto;

communicating said second derived value to said computing means which also has said second value of input electrical variable available thereto;

calculating a calibration factor within said computing means according to the relationship;

said calibration factor is related to said second value of input electrical variable and said second derived value; and

communicating said calibration factor to said offset coefficient memory region for digital placement therein and subsequent use by said monitor in performing said function.

8. A process for calculating an offset coefficient and a digital calibration factor for a circuit breaker that acts in the presence of a predetermined value of an input electrical variable at an input of said circuit breaker to perform a function, where said offset coefficient and said calibration factor are digitally stored in a memory region of said circuit breaker and where any input electrical value within a range of input electrical values provides a corresponding derived electrical value in said circuit breaker, comprising the steps of:

supplying a first value of said input electrical variable to said input where said first value is zero;

sensing said supplied input electrical variable and producing in said circuit breaker a corresponding first derived value related thereto;

communicating said first derived value to a computing means;

calculating an offset coefficient within said computing means according to the relationship;

said offset coefficient equals said first derived value;

communicating said offset coefficient to said memory region for digital placement therein and subsequent use by said circuit breaker in performing said function;

supplying a second value of said input electrical variable to said input;

sensing said supplied second input electrical variable and producing in said circuit breaker a corresponding second derived value related thereto;

communicating said second derived value to said computing means which also has said second value of input electrical variable available thereto;

calculating a calibration factor within said computing means according to the relationship;

said calibration factor is related to said second value of input electrical variable and said second derived value; and

communicating said calibration factor to said offset coefficient memory region for digital placement therein and subsequent use by said circuit breaker in performing said function.

9. A process for calculating an offset coefficient and a digital calibration factor for a motor controller that acts in the presence of a predetermined value of an input electrical variable at an input of said motor controller to perform a function, where said offset coefficient and said calibration factor are digitally stored in a memory region of said motor controller and where any input electrical value within a range of input electrical values provides a corresponding derived electrical value in said motor controller, comprising the steps of:

supplying a first value of said input electrical variable to said input where said first value is zero;

sensing said supplied input electrical variable and producing in said motor controller a corresponding first derived value related thereto;

communicating said first derived value to a computing means;

calculating an offset coefficient within said computing means according to the relationship;

said offset coefficient equals said first derived value;

communicating said offset coefficient to said memory region for digital placement therein and subsequent use by said motor controller in performing said function;

supplying a second value of said input electrical variable to said input;

sensing said supplied second input electrical variable and producing in said motor controller a corresponding second derived value related thereto;

communicating said second derived value to said computing means which also has said second value of input electrical variable available thereto;

calculating a calibration factor within said computing means according to the relationship;

said calibration factor is related to said second value of said input electrical variable and said second derived value; and

communicating said calibration factor to said offset coefficient memory region for digital placement therein and subsequent use by said motor controller in performing said function.