Apparatus, system, and/or method for protection and control of an electrical device

• US 8,300,372 B2
• Filed: 04/04/2007
• Issued: 10/30/2012
• Est. Priority Date: 04/04/2006
• Status: Active Grant

• Current Assignee: Cerus Industrial Corporation
• Original Assignee: Cerus Industrial Corporation
• Inventors: Holce, Kent Jeffrey, Perra, Andre Pierre, Cota, Roger Steven
• Primary Examiner(s): Fureman, Jared
• Assistant Examiner(s): BAUER, SCOTT ALLEN
• Application Number:
  US11/784,117
• Publication Number:
  US 20080094768A1
• Time in Patent Office: 2,036 Days
• Field of Search: 361/79, 361/93.1, 361/93.2
• US Class Current: 361/79
• CPC Class Codes: A61K 31/53 having six-membered rings with three nitrogens as the only ring hetero atoms, e.g. chlorazanil, melamine melarsoprol A61K31/555 ; with four nitrogen atoms A61K31/495

Abstract

An electrical device protection apparatus, such as an overload relay, can include a microprocessor 102 that can receive a wide range of current signals from a current transformer or other current sensor. Also microprocessor 102 can employ a voltage sensor 112 to measure line voltage, for representing true power, and as a power supply 114 source for the microprocessor 102. The microprocessor can then generate annunciation signals 118, control signals 120, and/or communication signals 122 as necessary for the control and/or protection of an attached electrical device.

Claims

1. An apparatus for providing overload thermal protection and control of a motor or electrical device having a motor, comprising:

a current transformer provisioned for measuring power supply line current supplied to a motor or electrical device having a motor, with substantial accuracy over a wide current range; and

a microprocessor configured for;

receiving a current input signal corresponding to the power supply line current measured by the current transformer;

receiving a voltage input signal corresponding to a voltage measured from the power supply line powering the motor or electrical device having a motor;

identifying a classification of the motor or electrical device having a motor, and a corresponding overload thermal protection value, based, at least in part, on at least one of the received current input signal or the received voltage input signal; and

implementing control logic to set a set point for operating the motor or electrical device having a motor consistent with the identified classification and corresponding overload thermal protection value.

2. The apparatus of claim 1, wherein the microprocessor derives operating power from the power supply powering the motor or electrical device having a motor.

3. The apparatus of claim 1, wherein the microprocessor identifies the classification of the motor or electrical device having a motor by comparing an in-rush current to a full load current for the motor or electrical device having a motor.

4. The apparatus of claim 1, wherein the microprocessor identifies the classification of the motor or electrical device having a motor based, at least in part, on a phase-angle load characteristic.

5. The apparatus of claim 1, wherein the microprocessor is programmed to discern loss of load to the motor or electrical device having a motor in response to detecting rapid changes in amperage or power.

6. The apparatus of claim 1, wherein the microprocessor is configured to send an interrogation signal to the motor or electrical device having a motor and, in response to sending the interrogation signal, receive a return signal or identify a circuit characteristic for use in identifying the classification of the motor or electrical device having a motor.

7. The apparatus of claim 1, wherein the current transformer is constructed of a material substantially resistant to core saturation.

8. The apparatus of claim 7, wherein the material is non-magnetic.

9. The apparatus of claim 1, wherein the current transformer is a Rogowski current transformer.

10. The apparatus of claim 9, wherein the Rogowski current transformer is printed on a printed circuit board.

11. The apparatus of claim 10, wherein the microprocessor is mounted to the printed circuit board.

12. The apparatus of claim 9, wherein the Rogowski current transformer is torroidally wound over a cylindrically shaped core so as to to enhance signal gain for low current applications.

13. The apparatus of claim 9, further comprising a differential noise canceling loop circuit to substantially resist electromagnetic interference and enable accurate current measurement at a low current input value.

14. The apparatus of claim 13, wherein the low current input values correspond to a current below 1 Ampere.

15. The apparatus of claim 1, wherein the wide current range corresponds to a range substantially between 0.1-40 Amperes.

16. The apparatus of claim 1, further comprising an analog to digital converter.

17. The apparatus of claim 16 wherein the analog to digital converter is an 18-bit converter.

18. The apparatus of claim 16, wherein the analog to digital converter is a 10-bit converter.

19. The apparatus of claim 18, further comprising a pre-scaler circuit element to scale a signal input to the analog to digital converter.

20. The apparatus of claim 19, wherein the pre-scaler is a digital potentiometer or pulse width modulator.

21. The apparatus of claim 1, further comprising at least one manual control to limit the current transformer to measuring within an expected subset current range, the expected subset current range being a limited range within the wide current range.

22. The apparatus of claim 1, further comprising a latching contact relay.

23. The apparatus of claim 1, further comprising voltage input pins provisioned in conjunction with current transformer apertures for connection to a secondary control device.

24. The apparatus of claim 23, wherein the secondary control device is a mechanical contactor.

25. A method, comprising the steps of:

using a current transformer electromagnetically coupled to a power supply line, measuring at least one of an input signal or circuit characteristic of a power distribution circuit electromagnetically connected to a motor or electrical device having a motor;

based at least in part on the measured input signal or circuit characteristic, classifying the motor or electrical device having a motor; and

setting an overload thermal protection set point for the motor or electrical device having a motor based at least in part on the classification of the motor or electrical device having a motor.

26. The method of claim 25, wherein the measuring step includes measuring a load characteristic of the motor or electrical device having a motor.

27. The method of claim 26, wherein the load characteristic includes in-rush current.

28. The method of claim 26, wherein the load characteristic includes a phase-angle.

29. The method of claim 25, wherein

the measuring step includes sending an interrogation signal and either receiving a response signal or detecting a circuit characteristic;

and

the classifying step is based, at least in part, on the received response signal or detected circuit characteristic.

30. The method of 25, further comprising the step of drawing operating power from a line power source supplying power to the power distribution circuit, the operating power being used for conducting the measuring, classifying, and setting steps.

31. A system for controlling and providing thermal protection for a motor or electrical device having a motor, comprising:

a power supply line providing power to an a motor or electrical device having a motor;

a contactor relay for disconnecting power supplied to the motor or electrical device having a motor, via the power supply line, in response to an undesirable operating condition being determined to exist in the motor or electrical device having a motor; and

an overload protection relay including;

a current transformer for measuring current supplied to the motor or electrical device having a motor via the power supply line;

a microprocessor for identifying the motor or electrical device having a motor and setting one or more corresponding overload thermal protection set points to detect an occurrence of the undesirable operating condition in the motor or electrical device having a motor.

32. The system of claim 31, wherein the undesirable operating condition is an overload on the motor or electrical device having a motor.

33. The system of claim 31, wherein the undesirable operating condition is an under load on the motor or electrical device having a motor.

34. The system of claim 31, wherein the undesirable operating condition is an overload or an under load on the motor or electrical device having a motor.

35. The system of claim 31, wherein the contactor relay and the overload protection relay are provisioned in a single housing.

36. The system of claim 35, wherein the single housing corresponds to a starter mechanism for the motor or electrical device having a motor.