PROGNOSTIC SYSTEM FOR ROTATING MACHINES AND ASSOCIATED METHOD

FIELD OF INVENTION

[0001] The subject matter disclosed herein generally relates to rotating machines, for example, turbochargers. More specifically, the subject matter relate to a method and a system for prognosis of the rotating machine.

BACKGROUND OF THE INVENTION

[0002] A rotating machine, such as a turbocharger, typically has moving components like blades, rotor and a bearing. During the operation of a rotating machine, faults may develop in any of these components and which eventually may lead to the failure of the machine. Turbocharger failure is one of the causes of system failures of large internal combustion engines. The failures may be caused by a sudden or a progressive blade damages, bearing faults, rotor unbalance, or shudder. Sudden failures of rotating machines lead to unexpected downtime, thereby reducing productivity. Estimating life of the rotating machine may help in planning the maintenance schedules.

[0003] In many scenarios, rotating machine failure is falsely suspected for system failures and unnecessary inspection is taken up. Avoiding such inspections may reduce the downtime. Premature replacement of the machine incur unnecessary expense, whereas delay in repair and/or replacement of the machine could cause damage to the overall system.

[0004] There is a need for an effective in-situ system and method to prognose machine health for reducing the unexpected downtime and for easy maintenance.

BRIEF DESCRIPTION OF THE INVENTION

[0005] In accordance with one aspect of the present technique, a method is disclosed. The method includes receiving a signal indicative of a speed of a rotating machine. The method further includes determining an instantaneous angular speed based on the received signal. The method also includes determining an operating condition of the rotating machine based on the determined instantaneous angular speed.

[0006] In accordance with one aspect of the present systems, a system is disclosed. The system includes a detection module communicatively coupled to a rotating machine configured to receive a signal indicative of a speed of the rotating machine. The detection module is further configured to determine an instantaneous angular speed from the received signal. The detection module is also configured to determine an operating condition of the rotating machine based on the determined instantaneous angular speed.

[0007] In accordance with one aspect of the present systems, a system is disclosed. The system includes a speed sensor for measuring a speed of a rotating machine and a detection module communicatively coupled to the speed sensor. The detection module is configured to determine an instantaneous angular speed from the measured speed. The detection module is also configured to determine an operating condition of the rotating machine based on the determined instantaneous angular speed..

[0008] In accordance with another aspect of the present technique, a non-transitory computer readable medium encoded with a program to instruct a processing unit is disclosed. The program instructs a processing unit to enable receiving a signal indicative of a speed of a rotating machine enable determination of an instantaneous angular speed based on the acquired signal. The program further instructs the processing unit to enable determination of an operating condition of the rotating machine based on the determined instantaneous angular speed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 is a schematic diagram of a prognostic system for detecting an operating condition of a rotating machine in accordance with an exemplary embodiment;

[0010] FIG. 2 is a flow chart that illustrates the steps involved in determining instantaneous angular speed signal in accordance with an exemplary embodiment;

[0011] FIG. 3 illustrates a plot having a curve indicative of a signal indicative of speed of the rotating machine used with exemplary embodiment of FIG.2;

[0012] FIG. 4 illustrates a graph having a curve indicative of a frequency spectrum representative of a signal indicative of speed of the rotating machine in accordance with the embodiment of FIG. 3;

[0013] FIG. 5 illustrates a graph having a curve indicative of a frequency spectrum of a band pass filtered version of the signal indicative of speed of the rotating machine in accordance with an embodiment of FIG. 4;

[0014] FIG. 6 illustrates a graph having a curve indicative of an analytic signal in accordance with an exemplary embodiment of FIG. 2;

[0015] FIG. 7 illustrates a schematic representation of determining an analytic signal in accordance with an exemplary embodiment of FIG. 2;

[0016] FIG. 8 illustrates a graph having a curve indicative of an instantaneous phase signal determined from an analytic signal in accordance with an embodiment of FIG. 6;

[0017] FIG. 9 illustrates a graph having a curve indicative of an instantaneous angular speed signal derived from the instantaneous phase signal in accordance with an embodiment of FIG. 8;

[0018] FIG. 10 illustrates an alternate technique for determining an instantaneous angular speed signal in accordance with an exemplary embodiment;

[0019] FIG. 11 illustrates a graph having a curve indicative of an instantaneous angular speed signal determined in accordance with exemplary embodiment of FIG. 10;

[0020] FIG. 12 is a flow chart that illustrates the steps involved in determining condition of a rotating machine based on an instantaneous angular speed signal in accordance with an exemplary technique;

[0021] FIG. 13 is a flow chart illustrating the steps involved in determining a blade fault or a bearing fault condition in accordance with an exemplary technique;

[0022] FIG. 14 is a flow chart illustrating the steps involved in determining an unbalance or a shudder condition in accordance with an exemplary technique;

[0023] FIG. 15 is a flow chart that illustrates the steps involved in distinguishing a normal firing condition from a miss firing condition for an engine in accordance with an exemplary embodiment;

[0024] FIG. 16 is a graph having a curve indicative of IAS signals corresponding to normal firing and miss firing condition in accordance with an embodiment of FIG. 15; and

[0025] FIG. 17 illustrates a bar chart in accordance with an embodiment of FIG.
16.

DETAILED DESCRIPTION OF THE INVENTION

[0026] The present disclosure relates to a prognostic system and an associated method for a rotating machine. In particular, speed of a rotating machine is obtained and an instantaneous angular speed (IAS) of a signal indicative of the speed of the rotating machine is determined. Based on the instantaneous angular speed, an operating condition of the rotating machine is determined.

[0027] FIG. 1 is a diagrammatic illustration of a rotating machine 100 provided with a prognostic system 101. The rotating machine 100 includes a turbocharger 130 having a compressor 102 driven by a turbine 104. Fresh air is drawn into the compressor 102 via an inlet manifold 122. The compressed air from the compressor 102 is cooled via a cooler 108 and the cooled air is fed to an engine 110. Cooled air is mixed with a fuel and combusted in the engine 110. An exhaust gas 112 from the engine 110 is expanded in the turbine' 104 to generate power. The turbine 104 and the compressor 102 are mounted on a shaft 106. Although, a turbocharger is shown in the FIG. 1, the prognostic system 101 is not limited to the turbocharger. In other embodiments, the rotating machine 100 may include other rotating machine such as a motor, a generator, a turbine, or the like.

[0028] The prognostic system 101 includes a speed sensor 116 and a detection module 118. The speed sensor 116 acquires a signal 114 indicative of the speed of the shaft 106. The speed sensor 116 may be a Hall-effect sensor. The speed sensor 116 may also be any other magnetic sensor, a capacitive sensor or an optical sensor. The Hall-effect sensor is positioned near a toothed wheel encoder 128 fixed on or coupled to the shaft 106 of the rotating machine 100. The Hall-effect sensor produces a peak voltage when one of the tooth of the wheel 128 is in a position proximate to the sensor. The speed signal 114, acquired by the speed sensor 116, is processed by the detection module 118 to generate a signal indicative of a condition 120 of the rotating machine 100. The detection module 118 may include but not limited to a processing unit 124, a memory module 126, and other suitable hardware components to compute an operating condition of the rotating machine 100. The operating condition of the rotating machine 100 may include but not limited to a blade damage, a bearing fault, an unbalance, a shudder, or the like. In case of a turbocharger, the operating condition may also include a cylinder "miss firing condition" associated with the engine.

[0029] The processing unit 124 may include a controller, a general purpose processor, or a Digital Signal Processor (DSP). The processing unit 124 may receive additional inputs from a user through a control panel or any other input device including a keyboard. The memory module 126 may be a random access memory (RAM), read only memory (ROM) or any other type of computer readable memory accessible by the processing unit 124. The memory medium may be encoded with a program to instruct the processing unit 124 to enable a sequence of steps to determine an operating condition of the rotating machine 100.

[0030] The detection module 118 is configured to process a signal indicative of the speed of the rotating machine 100 to determine an instantaneous angular speed (IAS). The operating condition of the rotating machine 100 is determined based on the IAS signal. The detection module 118 is further configured to analyze instantaneous angular speed signal in time and frequency domains to derive various temporal and spectral features related to the IAS signal. Further, at least one of these temporal and spectral features may be used to derive a parameter that is indicative of an operating condition 120 of the rotating machine 100. The operating condition 120 of the rotating machine 100 may be determined based on the value of the derived parameter. Details of determining an IAS signal are explained in greater detail with reference to the subsequent figures.

[0031] FIG. 2 is a flow chart 200 illustrating an exemplary embodiment of a method for determining an instantaneous angular speed signal from the signal indicative of the speed of the rotating machine. A signal indicative of the measured speed is considered in step 202. In an alternate embodiment, the signal 202 may be a received signal indicative of speed of a turbocharger. The signal indicative of speed have a fundamental frequency represented by: (1)
where RPM is the speed of the turbocharger and p is the number of teeth on the toothed wheel encoder 128. A band pass filter of predetermined bandwidth centered at this fundamental frequency is used to select frequencies of interest from the signal indicative of the measured speed of the rotating machine as represented by the step 204. The band pass filter coefficients may be obtained from the memory module 126 and a sequence of instructions may be executed by the processing unit 124 to determine the band pass filtered signal.

[0032] A cosine function based dynamic model for the turbocharger speed signal is represented by:

where A is the peak amplitude turbocharger speed signal, w0 =2nfo is the angular frequency of the speed signal in radians, ./o is the frequency in Hettz, o0 is the phase of the speed signal and t is the independent variable time. If/0 is time variant represented by:

where, fs is a constant term, and m(t) is a time varying component with a scaling factor a,
Equation 2 may be represented by:

[0033] It should be noted from Equation 4 that the turbocharger speed is a time varying signal. The term is represent the contributions to the speed signal due to the rotations of the turbocharger shaft. The term m(t) represent the contributions of the exhaust gas generated by the engine to the speed signal. The term 0O is representative of the contributions of the turbocharger anomalies to the time varying speed signal.

[0034] Typically, the engine operates at a rotation speed of around a thousand RPM (rotations per minute) and the turbocharger shaft rotates at a relatively higher speed, for example, 7000 RPM. The speed sensor generates p pulses per rotation of the toothed wheel encoder. For e.g., when an eight toothed wheel is considered corresponding to p = 8, the speed measurements generate around 950 pulses per second. The signal m(t) has a frequency range of 5 to 50 Hz and 0O has a bandwidth of approximately 50 to 1500 Hz.

[0035] An instantaneous phase of the speed of the rotating machine is extracted from a transformed version of the filtered signal. Typically, a Hilbert transform may be applied to the band pass filtered signal to derive an instantaneous phase as represented by the step 206. In other embodiments, other transformations for deriving an instantaneous phase of the signal indicative of the speed of the rotating machine are envisioned. The derivation of the instantaneous phase represented by 208 is performed to determine the Instantaneous angular speed (IAS) signal as shown in the step 210.

[0036] An analytic signal u(t) is derived from the signal indicative of the speed s(t) using a Hilbert transform represented by:

u(t) = s(t) + iH(s(t)) (5)

where H(s(t)) is the Hilbert transformation of the signal s(t) and / is the unit imaginary number.
The signal u(t) of Equation 5 may also be represented by:
(6)

where, Au is the amplitude of the analytic signal, and 0u(t) is the phase of the analytic signal. Differentiation the polar form of the analytic signal is represented by:

(7) The ratio of Equation 6 and Equation 7 is represented by:
(8)

The derivative of the phase, which is an estimate of Instantaneous Angular Speed (IAS), is represented by:
(9).

[0037] FIG. 3 illustrates an example of intermediate signals generated in accordance with the method of FIG. 2 for determining an instantaneous angular speed signal from the signal indicative of the speed of the rotating machine. A typical signal indicative of speed of the rotating machine corresponding to step 202 of FIG. 2 is represented by a curve 300. The x-axis of the graph represents time in seconds and the y-axis represents the amplitude of the speed signal.

[0038] FIG. 4 illustrates a frequency domain representation 302 of the signal 300 of FIG. 3, as a spectrum. The x-axis of the graph represents frequency of the speed signal and the y-axis is representative of the magnitude of the spectrum. The spectrum is a magnitude spectrum of the signal indicative of the speed of the rotating machine.

[0039] FIG. 5 illustrates a band pass filtered version of the signal 302 of FIG. 4, represented by a curve 304. The curve of 304 is a frequency domain representation of the band pass filtered signal. The x-axis of the graph represents the frequency of the band pass filtered signal and y-axis represents the magnitude of the spectrum of the band pass filtered signal.

[0040] FIG. 6 illustrates an example of an analytic signal represented by the Equation 5. The analytic signal is represented by a curve 308. The x-axis represent* sample number corresponding to the samples of discretized version of the analytic signal and y-axis represents amplitude of the analytic signal. The analytic signal 308 is further represented by two curves 306 and 310. The curve 306 illustrates real component of the analytic signal and the curve 310 represents imaginary component of the analytic signal.

[0041] FIG. 7 illustrates a device 312 for generating an analytic signal. Signal Xr is
the real component of the analytic signal which is same as the input signal X. X, is the Hilbert transformation of the signal X, representing the imaginary component of the analytic signal. The analytic signal is represented by the svan

[0042] FIG. 8 illustrates an example of an instantaneous phase derived from the analytic signal of Equation 5, represented by a curve 314. The x-axis of the graph represents discrete time of the instantaneous phase signal indexed with sample number and y-axis represents phase angle of the instantaneous phase signal in radians.

[0043] FIG. 9 illustrates a derivative of the instantaneous phase signal, which is an estimate of Instantaneous Angular Speed (IAS), represented by the curve 316. The x-axis of the graph represents discrete time of the IAS signal indexed with sample numbers and the y-axis represents magnitude of the phase angle the IAS signal in radians.

[0044] It should be noted herein that in other embodiments, other techniques for determining IAS signal from the signal indicative of the speed of the rotating machine, are also envisioned. In one embodiment, a pulse time interval between two successive pulses of the signal indicative of speed of the rotating machine may be extracted to derive IAS signal. A pulse time interval sampler may be used for extracting the time interval between two successive pulses of the signal indicative of speed of the rotating machine. For example, a pulse width demodulator may be used as a pulse time interval sampler. In another embodiment, a phase locked loop (PLL) may be used as a pulse time interval sampler. In yet another embodiment, a high speed digital counter may be used as a pulse interval sampler.

[0045] FIG. 10 illustrates an alternate embodiment for determining the IAS signal.

A pulse time interval sampler 406 processes a signal 402 indicative of the speed of the rotating machine to determine an IAS signal 404.

[0046] FIG. 11 illustrates a curve 402 corresponding to the speed signal superimposed over a curve 404 which is representative of IAS signal derived using the pulse width demodulator. The x-axis of the graph 408 represent discrete time indexed with sample number of plotted signals and y-axis indicates the angular speed of the shaft in HZ.

[0047] FIG. 12 is a flow chart 500 illustrating an exemplary embodiment of a method for determining an operating condition of the rotating machine from the determined instantaneous angular speed. The method includes determining the instantaneous angular speed (IAS) based on the signal indicative of the speed of the rotating machine as represented by step 502. In one embodiment, a temporal feature of the IAS signal may be derived from the determined IAS signal as represented by the step 504. In another alternate embodiment, a frequency transformation of the IAS signal may be performed as indicated in step 506. One or more spectral features of the IAS signal may be determined as shown in the step 508. It should be noted herein that temporal features may be a signal derived from the IAS signal or a vector or a value related to the IAS signal. Similarly, a spectral feature may be another signal derived based on the frequency transformation of the IAS signal, or a vector derived based on the frequency transformation of the IAS signal. One or more of these features could be projected in time to derive additional features. A parameter may be derived based on one or more temporal or spectral features as indicated in the step 5!C. For example, a feature of an IAS signal may be its Fourier spectrum and an energy value derived from the samples of the frequency spectrum may be a parameter. In certain embodiments, the parameter may be a mean or a variance of a portion of the IAS signal. The determined parameter is compared with a threshold value in the step 512 to determine an operating condition of the rotating machine 514. When the parameter value exceeds the threshold value, the occurrence of an operating condition is confirmed. When the parameter value is less than the threshold value, the exemplary embodiment of method of FIG. 12 continues to operate with the availability of additional measurements.

[0048] The threshold value is determined based on many factors including but not limited to operating conditions of the rotating machine, environmental parameters, specifications of the machine and the reliability of determining an operating condition of the machine. For example, at least one of a baseline measurement, engine load, engine speed, exhaust temperature, and speed of the rotating machine may be used to determine the threshold value. It should be noted herein that the threshold vaiue may vary based on the type of the operating condition.

[0049] As discussed previously, the operating condition of the rotating machine may include but is not limited to blade damages, a bearing fault, an unbalance, or a shudder, or the like. In the absence of these faults, the IAS at every angular position of the toothed wheel encoder (or the shaft) may be the same when observed over a period of time. But, due to faulty conditions in blade and bearings, there will be a variation in the IAS signal values at certain angular positions of the toothed wheel when there is a presence of a fault condition. The variation may be quantified by various metrics. In one embodiment, a variance of the IAS signal may be considered. In another embodiment, an absolute value of the difference of the IAS signal from its mean could be used.

[0050] Referring to FIG. 13, a method 600 for determining an operating condition of a rotating machine is disclosed. IAS at various angular positions of the shaft is observed over a period of time as indicated in step 604. For example, when a toothed wheel encoder is mounted on the shaft of a rotating machine, a vector of IAS values at p angular positions corresponding to the p teeth are observed. Then a variance of the IAS at each of the positions are determined at step 606. Each of these variances is compared with a predefined threshold value in step 608. When a particular variance value of the vector exceed the threshold value 77, a blade damage or a bearing fault is determined in step 610. When the parameter value is less than the threshold value, the exemplary embodiment of method of FIG. 13 continues to operate with the availability of additional samples of IAS signal.

[0051] For example, with p = 8, the vector of variance of IAS signal at the eight angular positions corresponding to eight teeth of a wheel mounted on the shaft of the rotating machine is represented by:

where, v(n) is the variance vector determined at time instant n and ak(n) is the variance of IAS corresponding to A* angular position at 360k/8 degrees. Each element of the variance vector v(n) is compared with a threshold value Tj. When

(11) a blade damage (or a bearing fault) is detected.

[0052] The operating condition of a rotating machine may indicate a fault or a damage which could be incipient or critical. In order to identify the time to failure of the rotating machine, the parameter indicative of the operating condition may be projected in time. In one of the embodiments, the parameter quantifying the variation of the instantaneous angular speed is projected in time by using suitable mathematical model. For example, a dynamic model in a Kalman filter framework may be used to estimate the state variables of the model in an optimal way. The projected parameter value indicates a future value of the variation of the instantaneous angular speed. The projected parameter may be compared with a suitable threshold value. When the projected parameter exceeds the threshold, a time corresponding to the projected value of the parameter may be used to determine a time to failure of the rotating machine.

[0053] Referring to FIG. 14, a method 700 for determining an operating condition
of a rotating machine is disclosed. The method 700 includes determining the instantaneous angular speed (IAS) determined based on the signal indicative of the speed of the rotating machine as represented by step 702. The time-frequency representation of the IAS signal is performed at step 704. Energy values are estimated around the fundamental frequency as well as around several of the harmonics in step 706. The energy value could be an average of squared samples of the frequency spectrum of the IAS signal. The energy values are compared in step 708 with pre-determined threshold value. When the energy value exceeds a threshold value T2, an unbalance or a shudder condition of the rotating machine is determined in the step 710. When the parameter value is less than the threshold value, the exemplary embodiment of method of FIG. 14 continues to operate with the availability of additional samples of IAS signal.

[0054] Referring to FIG. 15, a method 800 for determining an operating condition of a rotating machine is disclosed. The method 800 includes determining the instantaneous angular speed (IAS) determined based on the signal indicative of the speed of the rotating machine as represented by step 802. A frequency transformation of the IAS signal is performed in step 804. A value of an area under a curve indicative of the frequency spectrum is determined in step 806. The value indicative of the area under the curve is compared in step 808 with a predefined threshold value. When the value indicative of the area under the curve is less than a threshold T3, a miss fire condition is determined in step 810. When the parameter value is more than the threshold value, the exemplary embodiment of method of FIG. 15 continues to operate with the availability of additional samples of IAS signal. In some embodiments, it may also be possible to identify the cylinder contributing to the miss fire condition based on the oscillations exhibited by the IAS signal.

[0055] FIG. 16 illustrates a graph 902 in accordance with the embodiment of FIG. 15. The graph 902 illustrates magnitude spectrum of the IAS signal with x-axis representing the frequency component of the IAS signal and y-axis representing the magnitude of the IAS signal. The IAS spectrum under normal firing condition 904 is superimposed with the IAS spectrum under miss firing condition 906. An area under the IAS spectrum is determined and is compared with a threshold T3. When the value of the area is less than the threshold value, a miss firing condition is determined.

[0056] FIG. 17 illustrates a bar chart 908 of the areas under the curves 904 and 906 (shown in FIG. 16). The height of each bar is representative of the area under the corresponding curve. In the illustrated embodiment, the bar 910 is representative of the normal firing condition with larger area which is clearly distinguishable from the bar 912 representative of the miss firing condition.

[0057] In accordance with the embodiments of the present invention, a signal indicative of the speed of the rotating machine includes information to detect various operating conditions of the machine. Use of the exemplary prognostic system and an associated method provides a means for preemptive detection of failures of rotating machine.

[0058] K is to be understood that not necessarily all such objects or advantages described above may be achieved in accordance with any particular embodiment. Thus, for example, those skilled in the art will recognize that the systems and techniques described herein may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein.

[0059] While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims. What is claimed as new and desired to be protected by Letters Patent of the United States is:

CLAIMS

What is claimed is:

1. A method, comprising:

receiving a signal indicative of a speed of a rotating machine;

determining an instantaneous angular speed based on the received signal; and

determining an operating condition of the rotating machine based on the determined instantaneous angular speed.

2. The method of claim 1, wherein determining the instantaneous angular speed comprises:

passing the received signal through a band pass filter to obtain a band pass filtered signal;

applying a frequency transformation to the band pass filtered signal to generate a transformed band pass filtered signal; and

determining an estimate of the instantaneous angular speed based on the transformed band pass filtered signal.

3. The method of claim 2, wherein applying the frequency transformation comprises applying a Hilbert transformation.

4. The method of claim 1, wherein determining the instantaneous angular speed comprises extracting a pulse time interval between two successive pulses of the received signal.

5. The method of claim 1, wherein the operating condition comprises at least one of a blade damage, a bearing fault, an imbalance condition, and shudder.

6. The method of claim 1, wherein determining the operating condition comprises at least one of:

extracting a temporal feature based on the determined instantaneous angular speed; and

extracting a spectral feature based on the determined instantaneous angular speed.

7. The method of claim 6, wherein determining the operating condition comprises:

determining a parameter based on at least one of the temporal feature and the spectral feature; and

comparing the parameter with a threshold value.

8. The method of claim 7, wherein determining the parameter comprises determining a variation of the determined instantaneous angular speed.

9. The method of claim 8, wherein determining the parameter comprises estimating a future value of the variation of the determined instantaneous angular speed.

10. The method of claim 7, wherein determining the parameter comprises:

determining a frequency spectrum of the determined instantaneous angular speed; and

determining an energy value based on a harmonic frequency of the frequency spectrum.

11. The method of claim 7, wherein determining the parameter comprises determining an area under a curve representative of a frequency spectrum of the determined instantaneous angular speed.

12. The method of claim 7, further comprising determining the threshold value based on at least one of a baseline measurement, engine load, engine speed, exhaust temperature, and speed of the rotating machine.

13. A system comprising:

a detection module communicatively coupled to a rotating machine configured to:

receive a signal indicative of a speed of the rotating machine;

determine an instantaneous angular speed from the received signal; and

determine an operating condition of the rotating machine based on the determined instantaneous angular speed.

14. The system of claim 13, wherein the detection module is configured to determine the instantaneous angular speed by:

passing the received signal through a band pass filter to obtain a band pass filtered signal;

applying a frequency transformation to the band pass filtered signal to generate a transformed band pass filtered signal; and

determining an estimate of the instantaneous angular speed based on the transformed band pass filtered signal.

15. The system of claim 13, wherein the detection module comprises a pulse time interval sampler configured to determine the instantaneous angular speed.

16. The system of claim 13, wherein the detection module is configured to determine the operating condition by at least one of:

extracting a temporal feature based on the determined instantaneous angular speed; and

extracting a spectral feature based on the determined instantaneous angular speed.

17. The system of claim 16, wherein the detection module is configured to determine the operating condition by:

determining a parameter based on at least one of the temporal feature and the spectral feature; and

comparing the parameter with a threshold value.

18. The system of claim 17, wherein the detection module is configured to determine the parameter by determining a variation of the determined instantaneous angular speed.

19. The system of claim 18, wherein the detection module is configured to determine the parameter by estimating a future value of the variation of the determined instantaneous angular speed.

20. The system of claim 17, wherein the detection module is configured to determine the parameter by:

determining a frequency spectrum of the determined instantaneous angular speed; and

determining an energy value based on a harmonic frequency of the frequency spectrum.

21. The system of claim 17, wherein the detection module is configured to determine the parameter by determining an area under a curve representative of a frequency spectrum of the determined instantaneous angular speed.

22. A system, comprising:

a speed sensor for measuring a speed of a rotating machine; and

a detection module communicatively coupled to the speed sensor configured to:

determine an instantaneous angular speed from the measured speed; and

determine an operating condition of the rotating machine based on the determined instantaneous angular speed.

23. The system of claim 22, wherein the speed sensor comprises a Hall-effect sensor.

24. A non-transitory computer readable medium encoded with a program to instruct a processing unit to:

enable receiving a signal indicative of a speed of a rotating machine enable determination of an instantaneous angular speed based on the acquired signal; and

enable determination of an operating condition of the rotating machine based on the determined instantaneous angular speed.