US 6,529,135 B1 · Integrated electric motor monitor

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.

4 more elements

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.

8 more elements

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.

7 more elements

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.

2 more elements

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.

8 more elements

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.

8 more elements

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.

2 more elements

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.

26 more elements

Integrated electric motor monitor

Life of this patent

Integrated electric motor monitor

Life of this patent

Abstract

Claims38