Integrated electric motor monitor

• US 6,529,135 B1
• Filed: 10/12/1999
• Issued: 03/04/2003
• Est. Priority Date: 10/12/1999
• Status: Expired due to Term

• Current Assignee: Computational Systems Incorporated (Emerson Electric Company)
• Original Assignee: CSI Technology Incorporated (Emerson Electric Company)
• Inventors: Bowers, Stewart V., Childress, William E., Stevenson, James R.
• Primary Examiner(s): Wu, Daniel J.
• Assistant Examiner(s): Huang, Sihong
• Application Number:
  US09/415,824
• Time in Patent Office: 1,239 Days
• Field of Search: 340/648, 340/679, 340/635, 340/680, 340/682, 340/683, 318/806
• US Class Current: 340/648
• CPC Class Codes: G01R 31/343 in operation
• CPC Class Codes: H02P 23/0077 Characterised by the use of a particular software algorithm
• CPC Class Codes: H02P 29/024 Detecting a fault condition, e.g. short circuit, locked rotor, open circuit or loss of load

Abstract

A method monitors an operational condition of an electric motor, and stores in a memory device general trend, prognostic, diagnostic, and hazardous event information indicative of the motor'"'"'s operational condition. The method includes the steps of sensing characteristics indicative of the operational condition of the electric motor, such as vibration, temperature, magnetic flux, and the voltages applied to the motor'"'"'s windings, and generating sensor signals related to the sensed characteristics. Upon the occurrence of a first circumstance, such when measurements of the motor'"'"'s speed, winding temperature, and voltage, indicate that the motor is operating within its normal load profile, prognostic information is extracted from the sensor signals. The prognostic information provides a profile of the motor'"'"'s operational condition over time without the influences of fluctuating loads, temperature, and voltage. Upon the occurrence of a second circumstance, such as when the motor'"'"'s load factor is within a load factor range that is most common for the motor, diagnostic information is extracted from the sensor signals. The diagnostic information indicates the motor'"'"'s operational condition when it is operating within its most common load zone. Upon occurrence of a third circumstance, such as an indication that the motor is operating abnormally, hazardous event information is extracted from the sensor signals and stored. The hazardous event information indicates the motor'"'"'s condition at the time that a hazardous event, or fault, occurred. The general trend information is measured and stored at regular intervals to determine short- and long-term operational trends over time.

Claims

1. A method for monitoring an operational condition of an electric motor, and for storing in a memory device information indicative of the motor'"'"'s operational condition, where the motor rotates at a rotational speed to drive a load, generates vibration and magnetic flux, and attains a temperature when a voltage is applied to the motor, the method comprising the steps of:

(a) sensing characteristics indicative of the operational condition of the electric motor;

(b) generating sensor signals related to the sensed characteristics, the sensor signals including a speed signal, a temperature signal, and a voltage signal;

(c) extracting a speed value from the speed signal, a temperature value from the temperature signal, and a voltage value from the voltage signal, where the speed value, temperature value, and voltage value are numerical values indicative of the speed, temperature, and voltage, respectively, of the electric motor;

(d) combining the speed value, temperature value, and voltage value to form a profile prognosis value;

(e) during a learning period, repeating steps (a)-(d) n number of times to determine n number of profile prognosis values; and

(f) determining a most common profile prognosis value which is the profile prognosis value of the n number of profile prognosis values occurring most often during the learning period.

2. The method of claim 1 wherein the speed value comprises a decimal value having x number of digits, the temperature value comprises a decimal value having y number of digits, and the voltage value comprises a decimal value having z number of digits, and wherein step (d) further comprises combining the x digits of the speed value, the y digits of the temperature value, and the z digits of the voltage value to form the prognosis profile value having x+y+z number of digits.

3. The method of claim 2 wherein the speed value is a single digit value ranging from 0 to 9, the temperature value is a two-digit value ranging from 00 to 99, the voltage value is a single digit value ranging from 0 to 9, and the prognosis profile value is a four-digit value ranging from 0000 to 9999.

4. The method of claim 1 further comprising:

(g) during a period of time subsequent to the learning period, repeating steps (a)-(d);

(h) determining whether the profile prognosis value determined in step (g) is substantially equivalent to the most common profile prognosis value determined in step (f);

(i) if the profile prognosis value determined in step (g) is substantially equivalent to the most common profile prognosis value determined in step (f), gathering prognostic information from the sensor signals during the period of time subsequent to the learning period.

5. The method of claim 4 wherein the gathering of prognostic information in step (i) further comprises:

(i1) sensing the vibration of the electric motor;

(i2) generating a vibration signal based on the vibration; and

(i3) extracting vibration information from the vibration signal and storing the vibration information in the memory device.

6. The method of claim 5 wherein the steps of extracting vibration information from the vibration signal and storing the vibration information in the memory device further comprises generating a vibration spectrum based on the vibration signal and storing the vibration spectrum in the memory device.

7. The method of claim 4 wherein the gathering of prognostic information in step (i) further comprises:

(i1) sensing the flux of the electric motor;

(i2) generating a flux signal based on the flux; and

(i3) extracting flux information from the flux signal and storing the flux information in the memory device.

8. The method of claim 7 wherein the steps of extracting flux information from the flux signal and storing the flux information in the memory device further comprises generating a flux spectrum based on the flux signal and storing the flux spectrum in the memory device.

9. The method of claim 4 wherein the gathering of prognostic information in step (i) further comprises:

(i1) sensing the voltage of the electric motor;

(i2) generating a voltage signal based on the voltage; and

(i3) extracting voltage information from the voltage signal and storing the voltage information in the memory device.

10. The method of claim 9 wherein the steps of extracting voltage information from the voltage signal and storing the voltage information in the memory device further comprises generating a voltage spectrum based on the voltage signal and storing the voltage spectrum in the memory device.

11. The method of claim 1 wherein the step of determining prognostic information further comprises:

extracting sensor values from at least one sensor signal at periodic intervals during first and second time periods, where the sensor values are indicative of at least one sensed characteristic, and where the second time period follows the first time period;

determining into which of several predetermined ranges each sensor value falls at each interval during the first and second time periods;

determining a prognosis profile value based on the sensor values;

determining a normal range for the prognosis profile value, where the normal range is a range within which the prognosis profile value most often falls during the first time period;

determining that the first circumstance has occurred when the prognosis profile value falls within the normal range; and

extracting information from the sensor signals and storing the information in the memory device at periodic intervals during the second time period upon each occurrence of the first circumstance.

12. The method of claim 1 wherein step (c) further comprises:

(c1) determining into which of several predetermined speed ranges the speed signal falls;

(c2) determining the speed value based upon the predetermined speed range determined in step (c1);

(c3) determining into which of several predetermined voltage ranges the voltage signal falls; and

(c4) determining the voltage value based upon the predetermined voltage range determined in step (c3).

14. The method of claim 5 wherein:

step;

(a) further comprises sensing the voltage, flux, temperature, and vibration;

step (b) further comprises generating voltage, flux, temperature, and vibration signals based on the sensed characteristics; and

determining diagnostic information in step (e) further comprises extracting voltage, flux, temperature, and vibration information from the voltage, flux, temperature, and vibration signals.

15. The method of claim 14 wherein the step of determining diagnostic information further comprises:

generating a vibration spectrum based on the vibration signal;

generating a flux spectrum based on the flux signal;

generating a voltage spectrum based on the voltage signal; and

storing the vibration, flux, and voltage spectra in the memory device.

13. A method for monitoring an operational condition of an electric motor, and for storing in a memory device information indicative of the motor'"'"'s operational condition, where the motor rotates at a rotational speed to drive a load, generates vibration and magnetic flux, and attains a temperature when a voltage is applied to the motor, the method comprising the steps of:

(a) sensing characteristics indicative of the operational condition of the electric motor;

(b) generating sensor signals related to the sensed characteristics;

(c) determining a percent load factor corresponding to the load driven by the motor;

(d) determining whether the percent load factor is within a load factor range that is most common for the motor; and

(e) if the percent load factor is within the load factor range that is most common for the motor, determining diagnostic information from the sensor signals, where the diagnostic information is indicative of the motor'"'"'s typical operational condition.

16. A method for monitoring an operational condition of an electric motor, and for storing in a memory device information indicative of the motor'"'"'s operational condition, where the motor rotates at a rotational speed to drive a load, generates vibration and magnetic flux, and attains a temperature when a voltage is applied to the motor, the method comprising the steps of:

(a) sensing characteristics indicative of the operational condition of the electric motor;

(b) generating a plurality of sensor signals related to the sensed characteristics;

(c) determining at a first time whether at least one value associated with any of the sensor signals exceeds a predetermined threshold level;

(d) when it is determined that at least one value associated with any of the sensor signals exceeds the predetermined threshold level at the first time;

(d1) generating an alarm signal; and

(d2) storing hazardous event information indicative of the motor'"'"'s operational condition;

(d3) designating the at least one value that exceeds the predetermined threshold level at the first time as locked out of alarm;

(e) determining at a second time subsequent to the first time whether the at least one value designated as locked out of alarm continues to exceed the threshold level at the second time; and

(f) when it is determined that the at least one value designated as locked out of alarm continues to exceed the threshold level at the second time, determining whether to redesignate the at least one value previously designated as locked out of alarm to not locked out of alarm based upon one or more characteristics of the value previously designated as locked out of alarm.

17. The method of claim 16 wherein step (f) further comprises:

(f1) determining at the second time whether the at least one value designated as locked out of alarm has changed by at least a predetermined amount; and

(f2) when it is determined that the at least one value designated as locked out of alarm has changed by at least the predetermined amount at the second time;

(f2i) designating the at least one value previously designated as locked out of alarm as not locked out of alarm;

(f2ii) generating an alarm signal; and

(f2iii) storing hazardous event information indicative of the motor'"'"'s operational condition.

18. The method of claim 16 wherein step (f) further comprises:

(f1) determining at the second time whether the at least one value designated as locked out of alarm has changed by at least a predetermined amount; and

(f2) when it is determined that the at least one value designated as locked out of alarm has not changed by at least the predetermined amount at the second time, maintaining the designation of locked out of alarm for the at least one value previously designated as locked out of alarm.

19. The method of claim 16 wherein step (f) further comprises:

(f1) determining at the second time whether at least a maximum lock-out time has elapsed since the at least one value designated as locked out of alarm was first designated as locked out of alarm; and

(f2) if it is determined that at least the maximum lock-out time has elapsed since the at least one value designated as locked out of alarm was first designated as locked out of alarm,

(f2i) designating the at least one value previously designated as locked out of alarm as not locked out of alarm;

(f2ii) generating an alarm signal; and

(f2iii) storing hazardous event information indicative of the motor'"'"'s operational condition.

20. A method for monitoring an operational condition of an electric motor, and for storing in a memory device information indicative of the motor'"'"'s operational condition, where the motor rotates at a rotational speed to drive a load, generates vibration and magnetic flux, and attains a temperature when a voltage is applied to the motor, and where the memory device includes m number of storage locations, the method comprising the steps of:

(a) sensing characteristics indicative of the operational condition of the electric motor;

(b) generating a plurality of sensor signals related to the sensed characteristics;

(c) extracting sensor information from the sensor signals;

(d) determining whether at least one value associated with any of the sensor signals exceeds a predetermined threshold level;

(e) if at least one value associated with any of the sensor signals exceeds the predetermined threshold level,

(e1) determining a current identification value indicating each of the plurality of sensor signals that is associated with a value that exceeds the predetermined threshold level; and

(e2) storing the current identification value and associated sensor information in an mth storage location in the memory device;

(f) determining whether all of the m−

1 storage locations in the memory device other than the mth location are occupied by information; and

(g) if all of the m−

1 storage locations other than the mth location are not occupied by information, copying the current identification value and associated sensor information to an available storage location in the memory device.

21. A method for monitoring an operational condition of an electric motor, and for storing in a memory device information indicative of the motor'"'"'s operational condition, where the motor rotates at a rotational speed to drive a load, generates vibration and magnetic flux, and attains a temperature when a voltage is applied to the motor, and where the memory device includes m number of storage locations, the method comprising the steps of:

(a) sensing characteristics indicative of the operational condition of the electric motor;

(b) generating a plurality of sensor signals related to the sensed characteristics;

(c) extracting sensor information from the sensor signals;

(d) determining whether at least one value associated with any of the sensor signals exceeds a predetermined threshold level;

(e) if at least one value associated with any of the sensor signals exceeds the predetermined threshold level;

(e1) determining a current identification value indicating each of the plurality of sensor signals that is associated with a value that exceeds the predetermined threshold level, and

(e2) storing the current identification value and associated sensor information in an mth storage location in the memory device;

(f) determining whether all of the m−

1 storage locations other than the mth location are occupied by information; and

(g) if all of the m−

1 storage locations other than the mth location are occupied by information, retrieving an identification value from a first retrieval location, where the first retrieval location is one of the m−

1 storage locations other than the mth location, and determining whether the identification value retrieved from the first retrieval location is equivalent to the current identification value.

22. The method of claim 21 further comprising:

(h) if the identification value retrieved from the first retrieval location is equivalent to the current identification value, storing the current identification value and the associated sensor information to the first retrieval location.

23. The method of claim 21 further comprising:

(h) if the identification value retrieved from the first retrieval location is not equivalent to the current identification value, retrieving an identification value from a second retrieval location, where the second retrieval location is one of the m−

1 storage locations other than the mth location and the first retrieval location, and determining whether the identification value retrieved from the second retrieval location is equivalent to the current identification value.

24. The method of claim 21 further comprising:

(h) determining a current priority value associated with the current identification value;

(i) determining a first retrieval priority value associated with the identification value retrieved from the first retrieval location; and

(j) if the current priority value is greater than the first retrieval priority value, storing the current identification value and the associated sensor information to an m−

1 storage location.

25. A method for monitoring an operational condition of an electric motor having a rated load factor that rotates at a rotational speed to drive a load, generates vibration and magnetic flux, and attains a temperature when a voltage is applied to the motor, and for providing an indication to monitoring personnel of how well suited the motor is to drive the load under particular load conditions, the method comprising the steps of:

(a) sensing characteristics indicative of the load conditions;

(b) generating a plurality of sensor signals related to the sensed characteristics;

(c) determining diagnostic information indicative of the motor'"'"'s normal operation, including determining an average load factor indicative of the load conditions based on at least one of the sensor signals; and

(d) determining a numerical compatibility factor that quantifies, based on the average load factor and the rated load factor, how well suited the motor is to drive the load under the particular load conditions.

26. A method for monitoring an operational condition of an electric motor that rotates at a rotational speed to drive driven equipment, generates vibration and magnetic flux, and attains a temperature when a voltage is applied to the motor, and for ascertaining motor information indicative of the operational condition of the motor and the driven equipment, the method comprising the steps of:

providing equipment data about the driven equipment;

sensing a characteristic of the electric motor while the motor is driving the driven equipment;

generating a sensor signal related to the sensed characteristic; and

extracting driven equipment information from the sensor signal based on the equipment data, where the extracted driven equipment information depends at least in part upon the equipment data and relates to the operational condition of the driven equipment.

27. The method of claim 26, wherein the driven equipment includes a coupling that couples the motor to the driven equipment, the method further comprising the steps of:

providing coupling data about the coupling; and

extracting coupling information from the sensor signal based on the coupling data, where the extracted coupling information depends at least in part upon the coupling data and relates to an operational condition of the coupling.

28. The method of claim 26 further comprising:

storing the equipment information in a memory device;

accessing the equipment information from the memory device;

ascertaining, based upon the equipment information, equipment rotational frequency bands related to rotational frequency characteristics of the driven equipment while the driven equipment is being driven by the motor; and

extracting the motor information from the sensor signal based upon the equipment rotational frequency bands.

29. The method of claim 26 further comprising the step of determining, based upon the motor information, whether the operational condition of the motor is normal or abnormal.

30. The apparatus of claim 29 wherein the winding temperature monitor circuit further comprises:

a memory device for storing a predetermined threshold value; and

a controller for receiving the winding temperature signal, for accessing the predetermined threshold value from the memory device, for comparing the amplitude of the winding temperature signal to the predetermined threshold value, and for producing the second alarm signal when the amplitude of the winding temperature signal exceeds the threshold value.

31. The apparatus of claim 29 wherein the annunciator circuit further comprises a relay switch that changes state when the annunciator circuit receives the first or second alarm signal.

32. An apparatus for monitoring operational characteristics of an electric induction motor over a period of time, the motor having a winding and having a rotor that rotates at a rotational speed to drive a load, the rotor supported at one end by a first bearing and supported at an opposing end by a second bearing, the first and second bearings, which are supported by a motor frame, enabling rotation of the rotor relative to a stator, the motor generating vibration and magnetic flux, and attaining a temperature when a voltage is applied to the winding, the apparatus comprising:

a temperature sensor disposed adjacent to the winding for sensing the winding temperature and generating a winding temperature signal having an amplitude related to the winding temperature;

a processor for receiving the winding temperature signal and for extracting winding temperature information from the winding temperature signal, the processor further operable to determine, based on the amplitude of the winding temperature signal, when the motor is operating abnormally, and for generating an alarm signal when the amplitude of the winding temperature signal indicates that the motor is operating abnormally;

a first memory device for receiving and storing the winding temperature information; and

a winding temperature monitor circuit for receiving and continuously monitoring the winding temperature signal, for determining, based on the amplitude of the winding temperature signal, when the motor is operating abnormally, and for generating an alarm signal when the amplitude of the winding temperature signal indicates that the motor is operating abnormally, the winding temperature monitor circuit comprising;

a second memory device for storing a predetermined threshold value and a predetermined time limit; and

a controller for accessing the predetermined time limit and the predetermined threshold value from the second memory device, for determining a length of time during which the amplitude of the winding temperature signal exceeds the threshold value, for comparing the length of time to the predetermined time limit, and for generating the alarm signal when the length of time exceeds the predetermined time limit;

the processor further operable to receive the alarm signal, and to extract winding temperature information from the winding temperature signal when the alarm signal is received, the processor and the winding temperature monitor circuit thereby providing temperature monitoring redundancy; and

an annunciator circuit operable to receive the alarm signal to give an indication of an abnormal motor condition when the annunciator circuit receives the alarm signal.

33. An apparatus for monitoring operational characteristics of an electric induction motor over a period of time, the motor having a winding and having a rotor that rotates at a rotational speed to drive a load, the rotor supported at one end by a first bearing and supported at an opposing end by a second bearing, the first and second bearings, which are supported by a motor frame, enabling rotation of the rotor relative to a stator, the motor generating vibration and magnetic flux, and attaining a temperature when a voltage is applied to the winding, the apparatus comprising:

a temperature sensor disposed adjacent to the winding for sensing the winding temperature and generating a winding temperature signal having an amplitude related to the winding temperature;

a processor for receiving the winding temperature signal and for extracting winding temperature information from the winding temperature signal, the processor further operable to determine, based on the amplitude of the winding temperature signal, when the motor is operating abnormally, and for generating an alarm signal when the amplitude of the winding temperature signal indicates that the motor is operating abnormally;

a first memory device for receiving and storing the winding temperature information; and

a winding temperature monitor circuit for receiving and continuously monitoring the winding temperature signal, for determining, based on the amplitude of the winding temperature signal, when the motor is operating abnormally, and for generating an alarm signal when the amplitude of the winding temperature signal indicates that the motor is operating abnormally, the winding temperature monitor circuit comprising;

a second memory device for storing a predetermined threshold value and a predetermined time limit; and

a controller for accessing the predetermined time limit and the predetermined threshold value from the second memory device, for determining a length of time which begins when voltage is applied to the motor winding and which ends when the amplitude of the winding temperature signal exceeds the predetermined threshold value, and for generating the alarm signal when the length of time exceeds the predetermined time limit;

the processor and the winding temperature monitor circuit thereby providing temperature monitoring redundancy; and

an annunciator circuit operable to receive the alarm signal to give an indication of an abnormal motor condition when the annunciator circuit receives the alarm signal.

34. An apparatus for monitoring operational characteristics of an electric induction motor over a period of time, the motor having a winding and having a rotor that rotates at a rotational speed to drive a load, the rotor supported at one end by a first bearing and supported at an opposing end by a second bearing, the first and second bearings, which are supported by a motor frame, enabling rotation of the rotor relative to a stator, the motor generating vibration and magnetic flux, and attaining a temperature when a voltage is applied to the winding, the apparatus comprising:

a first temperature sensor disposed adjacent to the first bearing, the first temperature sensor generating a first temperature signal related to a first temperature level occurring adjacent to the first bearing;

a second temperature sensor disposed adjacent to the second bearing, the second temperature sensor generating a second temperature signal related to a second temperature level occurring adjacent to the second bearing;

differentiating means for receiving the first and second temperature signals, and for determining a temperature difference between the first and second temperature levels based upon the first and second temperature signals; and

annunciation means for generating an annunciation signal when the temperature difference exceeds a predetermined limit.

35. The apparatus of claim 34 further comprising:

the first temperature sensor generating an analog first temperature signal;

the second temperature sensor generating an analog second temperature signal;

analog-to-digital converter means for generating a digital first temperature signal based upon the analog first temperature signal, and for generating a digital second temperature signal based upon the analog second temperature signal;

the differentiating means further comprising a digital processor for receiving the digital first and second temperature signals, and for determining the temperature difference between the first and second temperature levels based upon the digital first and second temperature signals; and

the annunciation means further comprising the digital processor for generating the annunciation signal when the temperature difference exceeds the predetermined limit for at least a predetermined time period.

36. The apparatus of claim 34 wherein the annunciation means further generate the annunciation signal when the temperature difference exceeds a sum of the predetermined limit plus an integer multiple of a predetermined difference increase value.

37. An apparatus for monitoring operational characteristics of an electric induction motor over a period of time, the motor having a winding and having a rotor that rotates at a rotational speed to drive a load, the rotor supported at one end by a first bearing and supported at an opposing end by a second bearing, the first and second bearings, which are supported by a motor frame, enabling rotation of the rotor relative to a stator, the motor generating vibration and magnetic flux, and attaining a temperature when a voltage is applied to the winding, the apparatus comprising:

sensors integrated into the motor for sensing characteristics indicative of the operational condition of the motor and for generating a plurality of sensor signals related to the sensed characteristics;

a processor for calculating histograms indicative of the motor'"'"'s operational condition based on the sensor signals at periodic measurement intervals during the period of time, the histograms calculated by determining into which of a plurality of predetermined value ranges that the values fall at each periodic measurement interval, and determining at how many periodic measurement intervals the values fell into each of the plurality of predetermined value ranges during the period of time; and

a memory device for storing the histograms.

38. An apparatus for monitoring operational characteristics of an electric induction motor over a period of time, the motor having a winding and having a rotor that rotates at a rotational speed to drive a load, the rotor supported at one end by a first bearing and supported at an opposing end by a second bearing, the first and second bearings, which are supported by a motor frame, enabling rotation of the rotor relative to a stator, the motor generating vibration and magnetic flux, and attaining a temperature when a voltage is applied to the winding, the apparatus comprising:

temperature sensors for monitoring the temperature of the motor, the temperature sensors further comprising;

a first bearing temperature sensor disposed adjacent to the first bearing, the first bearing temperature sensor for generating a first bearing temperature sensor signal related to a first bearing temperature level occurring adjacent to the first bearing;

a second ;

bearing temperature sensor disposed adjacent to the second bearing, the second bearing temperature sensor for generating a second bearing temperature sensor signal related to a second bearing temperature level occurring adjacent to the second bearing;

an ambient temperature sensor for generating an ambient temperature sensor signal related to an ambient air temperature level occurring near the motor frame;

a frame temperature sensor disposed adjacent to the motor frame for generating an frame temperature sensor signal related to a frame temperature level occurring on the motor frame; and

a winding;

temperature sensor disposed adjacent to the winding, the winding temperature sensor for generating a winding temperature sensor signal related to a winding temperature level occurring adjacent to the winding;

a vibration sensor for monitoring the vibration of the motor and for generating a vibration sensor signal related to the motor vibration;

a flux sensor for monitoring the flux of the motor and for generating a flux sensor signal related to the motor flux;

a winding insulation sensor for monitoring characteristics of insulation in the winding and for generating a winding insulation sensor signal related to the insulation characteristics;

a voltage sensor for monitoring the voltage applied to the winding and for generating a voltage sensor signal related to the voltage;

a signal conditioning circuit for conditioning the vibration, voltage, and flux sensor signals, the signal conditioning circuit comprising;

a signal selection switch having an input and an output, for receiving the vibration and flux sensor signals at the input, for routing the vibration sensor signal to the output when the switch is in a first state, and for routing the flux sensor signal to the output when the switch is in a second state;

a filter circuit comprising;

a high pass filter for attenuating frequency components below a first cutoff frequency of the sensor signal at the output of the signal selection switch;

a low pass filter for attenuating frequency components above a first cutoff frequency of the sensor signal at the output of the signal selection switch; and

a filter selection switch for receiving the sensor signal at the output of the signal selection switch, for routing the sensor signal at the output of the signal selection switch to the high pass filter when the filter selection switch is in a first state, and for routing the sensor signal at the output of the signal selection switch to the low pass filter when the filter selection switch is in a second state; and

a gain adjust amplifier for adjusting the gain of the sensor signal at the output of the signal selection switch;

a winding temperature monitor circuit for receiving and continuously monitoring the winding temperature sensor signal, for determining when the amplitude of the winding temperature sensor signal exceeds a threshold, and for generating a first alarm signal when the amplitude of the winding temperature sensor signal exceeds the threshold; and

a first annunciator circuit that receives and is activated by the first alarm signal, the first annunciator circuit comprising a first relay switch that changes state when the first annunciator circuit receives the first alarm signal;

a processor for receiving the sensor signals, for extracting motor information from the sensor signals, for determining based on the motor information whether the motor is operating abnormally, for determining hazardous event information from the sensor signals when the motor is operating abnormally, for generating a second alarm signal when the motor is operating abnormally, for determining general sensor information when a predetermined period of time has elapsed since a last time that general sensor information was determined, for determining the motor'"'"'s speed based on the sensor signals, for determining a prognosis profile value based on the speed, temperature, and voltage signals, for determining a normal range within which the prognosis profile value typically falls, for determining prognostic information when the prognosis profile value falls within the normal range, for determining a load factor corresponding to the load driven by the motor and the load capacity of the motor, for determining whether the load factor falls within a most common load factor range for the motor, and for determining diagnostic information when the load factor falls within the most common load factor range;

a memory device for storing the hazardous event information, the general sensor information, the prognostic information, and the diagnostic information;

a second annunciator circuit that receives and is activated by the second alarm signal, the second annunciator circuit comprising a second relay switch that changes state when the second annunciator circuit receives the second alarm signal; and

a power conditioning circuit for receiving the voltage applied to the winding and conditioning the voltage to power the apparatus.