Study of broken bars in three-phase squirrel-cage induction motors at standstill

Abstract

This paper investigates the characteristic performance of broken bar faults in induction motors at standstill by 2D time-stepping finite-element and experiential approaches. Three identical rotors with the same stator are employed to generate one healthy-rotor, one-broken-bar and two-broken-bar fault cases in a three-phase 1.1-kW squirrel-cage induction motor. The focus is placed on how the broken bar affects air-gap flux density, stator and rotor currents, torque and magnetic force, as well as iron and rotor bar losses. Numerical results are validated by some experimental measurements obtained from a dedicated test rig.

Bi‐Signature optical spectroscopy for online fault detection in electrical machines

“… Before and after broken rotor fault on a squirrel cage rotor (a) Healthy rotor, (b) Broken rotor [18]…”

Cascaded signal processing approach for motor fault diagnosis

“…Fault diagnosis of variable frequency drive (VFD)-fed induction motor is the recent industrial demand. Rotor defects causes field imbalance, and hence, the stator current acquires the additional frequencies of order f s 6 2ksf s (Puche-Panadero et al, 2009;Sinha et al, 2018;Xie et al, 2012), where f s is supply frequency, s is slip and k is positive integer (including zero). Detection of rotor faults of squirrel-cage induction motor has various challenging issues such as identification of 2sf s sideband components at a low speed, cracked rotor bar detection and load torque oscillation.…”

Real‐time condition monitoring on VSD‐fed induction motors through statistical analysis and synchronous speed observation

“…The introduced approach uses standard statistical analyses like mean, variance, and information entropy, on one phase of the steady-state current signal provided by the VSD, together with sensorless synchronous speed estimation from the stator voltage supply, as inputs to an ANN for classifying the induction motor operational condition, different from reviewed literature, where a direct connection of the motor to the power supply is considered for simplicity and improved certainty of the used approach during the fault detection process. The introduced technique is able to detect distinct faults like BRB, misalignment (MAL), and unbalance (UNB) at different rotating speed, unlike previous approaches that detect just one single fault as bearings [6][7][8], rotor bars [9][10][11][12][13], and UNB [14][15][16][17][18] at a fixed rotating speed. Previous methods in reviewed literature use computationally complex signal processing techniques like WT [19][20][21][22][23], FT [24][25][26][27], and their combination with other techniques [28][29][30][31][32][33][34][35][36][37] for detecting multiple faults, which restrain them to off-line applications.…”

“…In , the instantaneous active and reactive power signature analyses are used for discriminating BRB and air gap eccentricity conditions from mechanical load oscillation effects in three‐phase squirrel cage induction motors. In , the effects of BRB in air‐gap flux density, stator and rotor currents, torque, and magnetic force at standstill are investigated through 2D time‐stepping finite‐element and experiential approaches. In , an approach for detecting BRB through electromagnetic torque monitoring is suggested using an asynchronous cage motor and finite element method analysis.…”