Abstract: An automated EL CID inspection technique for the stator core of an electrical machine is provided. The inspection device includes a rail, a pickup coil and a coil support assembly. The coil support assembly includes a first part movable along the rail, and a second part where the pickup coil is actually installed. The second part is movable jointly with the first part along the rail, while also being movable relative to the first part in a direction towards or away from the stator core. A motor actuates a motion of the coil support assembly. During inspection, the motor is activated, upon which the coil support assembly moves along the rail while a specified distance is maintained between the stator core and the pickup coil by the relative motion between the first and second parts. The technique is particularly applicable in a step-iron portion of the stator core.

Abstract: A systematic method and system for testing the charging and starting systems of a vehicle, which requires each individual test to pass before proceeding is provided. In addition, the invention incorporates an improved alternator test that determines whether the alternator belt is slipping using data read using a vehicle data port. Further, the invention provides a battery bank test that correlates the voltage before and after a load is applied to the battery bank to the batteries' conditions. When testing the starter, the oil temperature is read via the vehicle data port, allowing for a determination of whether the current draw is abnormally high.

Abstract: A method for testing rotation speed of a fan receives a duty cycle ratio related to the fan sent from a dial switch on a test board connected to the fan. The method transmits a pulse width modulation (PWM) signal based on the duty cycle to the fan to power rotation of the fan, then detects the PWM signal transmitted to the fan and a tachometer (TACH) signal transmitted from the fan. The method gathers the duty cycle ratio related to the fan from the PWM signal and an actual rotation speed of the fan from the TACH signal, and displays the duty cycle ratio and the actual rotation speed together on the test board.

Abstract: A method of sharing a test resource at a plurality of test sites executes respective test flows at the plurality of test sites with an offset in time, the respective test flows accessing the test resource at a predetermined position in the test flow.

Abstract: A method for monitoring a controller for controlling and/or monitoring a three-phase electric motor, in particular an asynchronous or synchronous motor, wherein two phase currents are measured and an error signal is generated if at least one of the two measured phase currents is essentially zero. An error signal is also generated if none of the two measured phase currents is essentially zero, but a sum formed of the two measured phase currents is essentially zero.

Abstract: Under a condition that rotor rotation speeds ?es are equal, winding wire currents Id, Iq are equal, and winding wire inductances Ld, Lq are equal in first and second electric motors (1, 2), a magnet temperature anomaly detector (30) provided in a microcomputer (5) calculates a change ratio d(|?ml??mr|)/dt of a magnetic flux difference between the first and second electric motors (1, 2) based on the difference Vql*?Vqr* between a q-axis voltage command value Vql* corresponding to the first electric motor (1) and a q-axis voltage command value Vqr corresponding to the second electric motor (2), and then when the change ratio d(|?ml??mr|)/dt of the magnetic flux difference is more than a predetermined threshold Sh1, it is determined that a permanent magnet of at least any one of the electric motors (1, 2) has a temperature anomaly.

Abstract: An inspection vehicle (24) for inspecting an air gap (14) between the rotor (11) and the stator (12) of a generator (10) includes drive elements (26, 27) for the independent progressive movement in the air gap (14). A particularly compact construction and flexible application is achieved by the drive elements (26, 27) being formed as elongated, flexionally elastic, torsionally rigid, magnetic rolls.

Abstract: Systems and methods for generating a collector flashover alert by passive monitoring of a generator are provided. One method includes receiving, by a computing device, signals from a current transformer coupled around an exciter cable connected to a generator collector assembly, determining, by the computing device, when a spark has occurred in the generator collector assembly based at least in part on received signals from the current transformer, generating an indication that a spark has occurred in the generator collector assembly when it is determined that a spark has occurred in the generator collector assembly, and generating a flashover alert based at least in part on the generated indication that a spark has occurred in the generator collector assembly.

Abstract: A method for analyzing electrical shorts in field windings of a synchronous machine having a rotor using a magnetic flux probe, the method includes: monitoring flux signals generated by the flux probe wherein the flux signals are indicative of magnetic flux emanating from the field windings; electronically storing flux data obtained from the monitored flux signals and indicative of electrical shorts in the field windings; automatically analyzing the stored flux data to identify field windings having the shorts and to count the shorts in each identified field winding, and automatically displaying information identifying the field windings with shorts and a number of shorts in each field winding.

Abstract: A method implemented using a controller based device includes receiving a measured electrical signal from an electrical device of an electromechanical device and receiving a measured vibration signal from a mechanical device of the electromechanical device, coupled to the electrical device. The method further includes determining a first signal signature based on the measured electrical signal and determining a second signal signature based on the measured vibration signal. The method also includes determining a diagnostic parameter based on the first signal signature and the second signal signature and determining a fault in the mechanical device based on the diagnostic parameter.

Abstract: A method of constructing an electric linear displacement motor for use in a testing device includes providing a stator having as stator housing with internal coils and a through bore extending from a first end of the stator housing to the second end of the housing. First and second end supports are connected to the first and second ends of the stator housing. An armature having magnets retained therein is inserted into the stator housing such of the armature is supported by the first end support and the second end support. A plurality of set screws are inserted into threaded openings proximate both the first end and the second end of the housing. The set screws then support and retain the armature such that there is an annular gap between the armature and the coils.

Abstract: A method for detecting and correcting for a step loss condition. A back electromagnetic force signal is measured and compared to a reference voltage. The motor continues operating and the back electromagnetic force signal is measured again and compared to the reference voltage. If the measured levels of the back emf voltages are less than the reference voltage, a step loss condition has occurred and the stator field is repositioned.

Abstract: An apparatus designed to accurately measure the capacitance required in order to optimize the power factor of single phase and three phase induction motors. Capacitor circuits are interruptably connected to the busses by means of push-button switches. Leads electrically connected to the busses are attached to a calculator unit which is, in turn, electrically connected to the load leads. The calculator unit displays in digital figures the actual operating conditions of an induction motor and the capacitance required for power factor optimization. The correct capacitance required to increase power factor in the 99% to 100% range is determined by either: (1) pushing a switch or a combination of switches, or (2) pushing the automatic mapping switch.

Abstract: A method and an arrangement are disclosed for detecting islanding operation of a distributed power generator. The method can include determining a frequency of a grid to which the distributed power generator is connected, measuring a rate of change of the frequency of the grid at an output of the distributed power generator, determining a threshold value for an alteration speed, comparing the rate of change of the frequency of the grid with the threshold value, and detecting islanding operation when the measured rate of change of the frequency exceeds the threshold value for a certain time period.

Abstract: A method of detecting a failure of an alternator supplying three-phase electricity to a load, the method comprising the steps of determining a duty ratio for each of the phases at the output of the alternator, determining phase differences between the phases at the output of the alternator; and determining the presence of a failure as a function of the phase differences and as a function of a comparison of the duty ratios. A power supply device is also provided for implementing the method.

Abstract: Insulation inspection method for an inverter-driven rotary electric machine includes: a step of applying, to an insulation sample (2), first impulse voltage simulating a voltage which occurs between winding turns of a rotary electric machine upon application of an inverter surge voltage to measure the number of times Nt-t that an impulse voltage is applied until the insulation sample (2) suffers from insulation breakdown; a step of applying the first impulse voltage to the insulation sample(2) to measure an occurrence frequency npd of partial discharge which occurs per one time application; step of applying a second impulse voltage simulating the inverter surge voltage to a rotary electric machine (3) to measure a partial discharge occurrence frequency npd(motor) between the winding turns which occurs per one time application; and determining that an insulation performance of the rotary electric machine (3) is acceptable.

Abstract: A method for discovering demagnetisation faults of a permanent magnet synchronous generator, such as a wind power generator. The method is performed during operation of the synchronous generator and includes measuring the vibration of the stator, performing a frequency analysis of the vibration, and deducing whether the generator suffers from demagnetization of a permanent magnet, from the vibration analysis. Moreover, geometric eccentricity faults and electric short circuit faults may also be detected from the vibration.

Abstract: An apparatus for testing number of turns, used for testing the number of turns of a winding coil on an electrical machine stator with concentrated winding, comprising: a base (6); a rod-shaped rotor bracket (4) around one end of which an excitation coil (1) is wound and around the other end of which a standard coil (2) is wound; a joining member for joining the base (6) with the rotor bracket (4) so that the base (6) and the rotor bracket (4) can rotate relative to each other, wherein the plane of the base (6) is parallel to the rotor bracket (4); a fixing member for fixing the electrical machine stator (5) with concentrated winding to the base (6) so as to make the stator (5) concentric and coplanar with the rotor bracket (4); a galvanometer (17) connected to the standard coil (2), which is connected to the tested coil (3) of the stator (5) in reverse polarity to form a loop during testing. Also provided is a method for using the apparatus to test the number of turns.

Abstract: A method for surge testing a bar-wound stator includes electrically connecting a conductive lead of a test system to a corresponding welded hair pin in each of the layers mid-way through the stator windings. A calibrated voltage surge is applied via the conductive leads into the windings of the stator at the welded hair pins. The method includes measuring a voltage drop between turns of the windings after applying the calibrated voltage surge, recording the measured voltage drop in memory of the test system, and executing a control event with respect to the stator when the measured voltage drop is more than a calibrated threshold voltage drop. A system for surge testing the bar-wound stator includes a test device having a capacitor for storing the calibrated surge voltage and a pin set that is electrically connected to the test device. The pin set includes the conductive wires and leads.

Abstract: A power generation system includes a support unit configured to support a power transmission line disposed on a transmission line tower, and a power generation unit. The support unit includes a support line having an end part connected to the power transmission line and a rotary body configured to rotate in a manner cooperating with the support line. The power generation unit is configured to generate electric power in response to rotation of the rotary body caused by movement of the support line resulting from tension of the power transmission line.

Abstract: A method of determining the magnetization level of permanent magnets of an electric machine, whereby a probe winding is placed in an electric machine having a stator with a plurality of stator winding, and a rotor with a plurality of permanent magnets; the probe winding is fixed with respect to the stator and links a magnetic flux produced by the permanent magnets; the rotor is rotated at an angular speed; an induced electric quantity is determined at terminals of the probe winding in response to passage of the permanent magnets; and the magnetization level of the permanent magnets is determined on the basis of the induced electric quantity detected.

Abstract: The method of detecting the failure of the excitation circuit of a polyphase alternator controlled by a regulator comprises the following steps: a) electrical information (Iexc) is continuously taken from the excitation circuit (1); b) the electrical information taken in step a) is continuously compared with a predetermined threshold value (Iref); c) a logic state (LT) is continuously determined according to the result of the comparison made in step b); and d) if the logic state (LT) determined in step c) persists for a time at least equal to a predetermined delay time (6), an electrical continuity fault of said excitation circuit is signalled. This method is particularly suitable for machines having a rotor equipped with permanent magnets or having a high remanence of the magnetic circuit of the rotor.

Abstract: The invention inter alia relates to a method for monitoring the bearing current of an electrical machine (10). An electrode (100) arranged at a distance (d) to a shaft and the shaft—due to the gap (S) between the electrode and the shaft—produce a measurement capacitance (C) and an electric shift current (i) which flows through the measurement capacitance when there is a temporal change of the voltage (Ug) applied between the shaft and the housing is measured. A measurement signal (Ms) indicating a bearing current flow is generated when the shift current or a measurement variable produced by the shift current meets a predetermined trigger criterion. Preferably, the electrode has a circular inner contour so that the gap is annular. The annular inner contour results in an error compensation in the case of a balance error of the shaft because the factor dC/dt remains at least substantially constant. Due to the contactless measurement of the shift current, no contact brushes for contacting the shaft are required.

Abstract: Provided are an apparatus and a method for diagnosing permanent magnet demagnetization of a permanent magnet synchronous motor. The apparatus includes a magnetic field generating unit, a stator current measuring unit, and a demagnetization diagnosing unit. The magnetic field generating unit generates magnetic fields of which directions are respectively parallel to a predetermined direction among a plurality of directions passing through a rotation axis of a rotor, on a plane vertical to the rotation axis of the rotor which is in a standstill. The stator current measuring unit measures currents which flow in a stator winding in correspondence with the respective generated magnetic fields.

Abstract: The electric machine comprises at least one winding made of a material having a temperature dependent resistance. The temperature of the winding is monitored using the resistance therein. Temperatures or resistances indicative of a fault can be sensed, and corrective action taken, without the need for dedicated temperature sensors.

Abstract: The invention relates to a method for detecting a malfunction of an electric machine, a first variable (isq) influencing the torque (M) of the electric machine (1) being modulated. In order to reliably detect the malfunction of an electric machine and to prevent an associated unwanted torque or power output of the electric machine, a second variable (?p) influencing the torque of the electric machine is modulated, the two variables (?p, isq) influencing the torque (M) cancelling each other out, when the electric machine functions properly, with respect to their effect onto a parameter of the electric machine (1), especially a torque (M), a speed, an electric parameter and/or a magnetic parameter, while it is concluded that there is a malfunction in the event of the lack of such a cancellation.

Abstract: Embodiments of the present invention relate to methods, systems, a machine-readable medium operable in a controller, and apparatus for controlling a multi-phase inverter that drives a multi-phase electric machine. When a sensor fault is detected, a phase current angle is computed based on the feedback stator currents, and used to estimate an angular velocity and an angular position of a rotor of the multi-phase electric machine. When the estimated angular velocity of the multi-phase electric machine is less than a transition angular velocity threshold, an open-circuit response can be applied at the multi-phase inverter by controlling all switches in the multi-phase inverter drive to be open. By contrast, when the estimated angular velocity is greater than the transition angular velocity threshold, a short-circuit response can be applied at the multi-phase inverter by controlling selected switches in the multi-phase inverter drive to connect all phases of the multi-phase inverter to a single bus (e.g.

Abstract: In a method for monitoring a rotating electric machine (1) that is fed by a converter and for diagnosing faults of said rotating electric machine, a current signature (I1, I2, I3) of output signals of the converter is recorded, the current signature (I1, I2, I3) is transformed, and the transformed current signature (A) is evaluated in at least one frequency band in order to detect damage to the machine (1).

Abstract: Accurately calculating location of a phase-to-phase fault even on a branched, non-homogenous, radial electric power distribution system. The calculation includes determining a calculated reactance to the fault without using positive-sequence current measurements, and uses the line parameters to determine locations on the system that match the calculated reactance to the fault. The calculation may further include a determination of faulted phase and eliminate fault location possibilities based on absence of the faulted phase at those locations.

Abstract: The invention concerns a method for detecting a fault in a rotating field machine, in which current components are analysed in a flux-based, particularly rotor-flux-based, coordinate system a flux-forming current component being subjected to a frequency analysis in the flux-based, particularly rotor-flux-based, coordinate system. It is endeavored to provide a simple method for an early detection of faults. For this purpose, a current operating point is detected for at least one predetermined supply frequency (fsp), said operating point being compared to a former operating point.

Abstract: A method is provided for monitoring and/or analysis of electrical machines during operation. An electrical machine has at least one generator with a shaft, an exciter system and drive device that drives the shaft. In this case, a first signal, which describes a voltage across a rotor winding, and a second signal, which describes a current flowing through the rotor winding, are measured simultaneously. The two signals are supplied to an analysis unit. The signals are split into individual frequency components in the analysis unit. The impedance of the rotor winding is then determined in order to identify fault states in the electrical machine.

Abstract: A power cable breaking detection method for a vehicle includes detecting currents of respective phases supplied to a three-phase motor from an inverter through at least a power cable, and a driving speed of the motor, determining whether the respective currents and the driving speed of the motor satisfy power cable breaking detection conditions, determining whether various conditions are satisfied with respect to a cable breaking sensing reference value of a current command performing cable breaking timer counting when the conditions are satisfied, and determining whether a predetermined period has elapsed such that a cable is considered broken when the predetermined period has elapsed.

Abstract: An automated EL CID inspection technique for the stator core of an electrical machine is provided. The inspection device includes a rail, a pickup coil and a coil support assembly. The coil support assembly includes a first part movable along the rail, and a second part where the pickup coil is actually installed. The second part is movable jointly with the first part along the rail, while also being movable relative to the first part in a direction towards or away from the stator core. A motor actuates a motion of the coil support assembly. During inspection, the motor is activated, upon which the coil support assembly moves along the rail while a specified distance is maintained between the stator core and the pickup coil by the relative motion between the first and second parts. The technique is particularly applicable in a step-iron portion of the stator core.

Abstract: A method for off-line testing of an electric motor is disclosed. The motor having at least one stator winding, and a rotor arranged along a rotation axis. The method includes applying a periodic test signal to the at least one stator winding; collecting first measuring data, related to a physical quantity of the at least one stator winding while the rotor is being rotated about the rotation axis, from one or more waveform periods of the test signal, detecting first peak values of the first measuring data; forming second measuring data based on the first detected peak values, detecting second peak values of the second measuring data for the at least one stator winding; determining a mutual relationship between the at least a portion of the second peak values; and, providing, if the mutual relationship deviates from a predetermined relationship, a signal indicating a fault in the rotor. Also disclosed is an apparatus for performing the disclosed methods.

Abstract: A method for diagnosing an electrical circuit including at least one electrical device, an actuator for the device controlled by a high side actuating switch and a low side actuating switch, and at least one additional switch not in series with any of the HS or LS switch, the method including: to each of the possible statuses of the circuit, giving a code; sequentially putting the circuit in at least some of these statuses for a given time period; during each of these periods, measuring voltage and/or current in different parts of the circuit and giving a code to the measurement; and establishing a diagnosis of correct functioning or of a malfunctioning of at least some elements of the circuit according to a pre-established correlation between the status codes and the measurement codes.

Abstract: A missing stator slot wedge in an electrical machine can be detected by analysing a current spectrum of the machine in a high frequency area. A current spectrum is provided from a current measurement, and values of the current spectrum in the high frequency area used to determine whether a stator slot wedge is missing or not. The conclusion can be based on values of a relative current amplitude IdB or on presence of certain harmonics in the high frequency area.

Abstract: An exemplary manipulator of a robot includes a detecting bar including two detecting pins and a regulating mechanism for regulating the distance between the two detecting pins, a fastening seat supporting the detecting bar, a fixing device fixed to the fastening seat, a driving mechanism disposed on the fastening seat, and an adjusting element connecting the driving mechanism with the regulating mechanism of the detecting bar. Under a driving action of the driving mechanism on the adjusting element, the adjusting element rotates to cause the regulating mechanism of the detecting bar to regulate the distance between the two detecting pins.

Abstract: An exemplary manipulator of a robot includes a fastening seat defining two guiding grooves, a driving mechanism disposed on the fastening seat, two transmitting plates respectively received in the two guiding grooves and cooperating with the driving mechanism, and two detecting bars each fixedly connecting with a corresponding transmitting plate. A detecting pin is fixed on each of the detecting bars. Under a driving action of the driving mechanism on the transmitting plates, the transmitting plates are activated to slide in the guiding grooves to cause the detecting bars to move close to or apart from each other, whereby a distance between the two detecting pins is automatically regulated.

Abstract: A current transformer assembly for use in an electrical monitoring system is described herein. The current transformer assembly includes a housing including a plurality of shielding members that at least partially define a cavity therein. The housing further includes an inner surface that defines an opening that extends therethough. A first current transformer is positioned within the housing. A second current transformer is positioned within the housing and is spaced a distance from the first current transformer to facilitate reducing electronic noise interference between the first and second current transformers.

Abstract: Methods and systems are provided for diagnosing faults of a rotor of an electric motor. A current is obtained for an inverter using a sensor. A preliminary angle is determined by a control unit or processor using a resolver angle of the rotor. A transformation is conducted by the control unit or processor using a transformation angle that is equal to a multiplier multiplied by the preliminary angle. A fault condition is identified via the control unit or processor using the transformation.

Abstract: A method for detecting whether the stator in a vehicle alternator has a turn-to-turn short circuit. The method includes determining an output current or voltage signal of the alternator, where the output current or voltage signal includes a ripple current frequency as a result of an AC-to-DC conversion. The method determines the speed of the alternator and a current output of the alternator. The method then determines the ripple current frequency of the alternator from the alternator speed, and determines a winding frequency from the ripple current frequency. The method performs an FFT analysis on the voltage and current signal, determines an amplitude of the winding frequency and compares the amplitude of the winding frequency to a predetermined amplitude, where if the difference exceeds a predetermined threshold, a turn-to-turn short circuit is likely occurring.

Abstract: A motor control device for a stepping motor including at least two phase coils and a rotor is provided. The motor control device includes a control unit which applies a pulse voltage subjected to pulse width modulation, to each of the at least two phase coils, a back electromotive voltage measuring unit which provides a halt period to temporarily halt the application of the pulse voltage to one of the phase coils when a direction of the coil current flowing in the one phase coil is switched, and which measures a back electromotive voltage induced in the one phase coil during the halt period, an out-of-step detecting unit which detects an out-of-step of the stepping motor if the measured back electromotive voltage satisfies a predetermined criterion, and a voltage control unit which sets a voltage for all phase coils other than the one phase coil to a constant voltage during the halt period.

Abstract: A method for surge testing a bar-wound stator includes electrically connecting a conductive lead of a test system to a corresponding welded hair pin in each of the layers mid-way through the stator windings. A calibrated voltage surge is applied via the conductive leads into the windings of the stator at the welded hair pins. The method includes measuring a voltage drop between turns of the windings after applying the calibrated voltage surge, recording the measured voltage drop in memory of the test system, and executing a control event with respect to the stator when the measured voltage drop is more than a calibrated threshold voltage drop. A system for surge testing the bar-wound stator includes a test device having a capacitor for storing the calibrated surge voltage and a pin set that is electrically connected to the test device. The pin set includes the conductive wires and leads.

Abstract: A detecting station of a winding product and a method for detecting an inter-turn short circuit are provided. The method includes following steps. First, a high voltage pulse is input to two ends of a winding of a winding product. Next, a voltage value of an electrifying process of the winding is extracted for generating an extracting data. Finally, a time-frequency converting operation is performed to the extracting data, and a time-frequency analysis information is generated for indicating whether or not the inter-turn short circuit is occurred in the winding.

Abstract: A method for detecting and correcting for a step loss condition. A back electromagnetic force signal is measured and compared to a reference voltage. The motor continues operating and the back electromagnetic force signal is measured again and compared to the reference voltage. If the measured levels of the back emf voltages are less than the reference voltage, a step loss condition has occurred and the stator field is repositioned.

Abstract: Systems, apparatuses, methods, and computer program products (i.e., software) for electric motor testing and analysis. Electric motor winding resistance and motor temperature are measured. The resistance measurement is normalized to a common temperature and electronically displayed in a resistance versus time graph including one or more previously normalized resistance values from previous resistance and temperature measurements. Based on information from the graph, a prediction or estimation can be made as to the remaining acceptable or satisfactory operating time of the electric motor. Such prediction or estimation may be used as an indicator for replacing or refurbishing the electric motor, or as an indicator for performing preventative maintenance on the electric motor.

Abstract: With a rotating electric machine testing method for applying a test voltage to an armature winding of the rotating electric machine to thereby test insulation performance of the armature winding, in the case where a rated voltage of the armature winding of the rotating electric machine is E, and an insulation test voltage of an armature winding of a sine wave voltage drive rotating electric machine at the rated voltage E is E/?{square root over (3)} or E, a test voltage Vtest applied to an armature winding of the inverter drive rotating electric machine is set to Vtest=?·E/?{square root over (3)} or Vtest?=?·E, respectively, provided that ?(=tinv/tsin), if the insulation thicknesses of the sine wave drive rotating electric machine is tsin and of the inverter drive rotating electric machine is tinv, thereby conducting a test on any of the AC voltage-current characteristic, AC tan ?, and AC partial-discharge characteristics.

Abstract: A current transformer assembly for use in an electrical monitoring system is described herein. The current transformer assembly includes a housing including a plurality of shielding members that at least partially define a cavity therein. The housing further includes an inner surface that defines an opening that extends therethough. A first current transformer is positioned within the housing. A second current transformer is positioned within the housing and is spaced a distance from the first current transformer to facilitate reducing electronic noise interference between the first and second current transformers.

Abstract: Methods and apparatus are provided for detecting a phase current sensor fault in a multi-phase electrical motor. The method comprises, receiving an input torque command T* and measuring a set of feedback signals of the motor including a phase current Ix for each of the phases of the motor, generating direct and quadrature command phase currents Id*, Iq* for the motor corresponding to a value of the input torque command T*, determining a total command current Is=[(Iq*)2+(Id*)2]½, generating a negative sequence current Ineg, where for three phases Ineg=(?)[Ia+(?2)Ib+(?)Ic], where ?=ej2?/3, combining Ineg and Is to provide a normalized negative sequence current Inn=Ineg/Is, comparing the normalized negative sequence current Inn to a predetermined threshold value INN* to determine the presence of a phase current sensor fault, and executing a control action when Inn>INN*.

Abstract: A system and method for detecting a rotor fault condition in an AC induction machine is disclosed. The system includes a processor programmed to receive voltage and current data from an AC induction machine, generate a current frequency spectrum from the current data, and identify rotor-fault related harmonics in the current frequency spectrum. The processor is also programmed to calculate a fault severity indicator using the voltage and current data, identified rotor-fault related harmonics, and motor specifications, analyze the fault severity indicator to determine a possibility of rotor fault. The processor generates an alert based on the possibility of rotor fault.