  Condition monitoring of induction motor has been widely researched over
recent years due to its ability to monitor operating characteristics and the
health status of induction motor. Various methods have been used to monitor
induction motors such as thermal monitoring and vibration analysis. This paper
introduces an alternative method which is to use an inductive coupling method
to extract in-circuit impedance of induction motor. This method allows for an
online measurement of the system under test (SUT) preventing any unnecessary
shutdowns. These unnecessary shutdowns may incur a loss of revenue for relevant
industries that depends heavily on induction motor operations. Two sets of
experiments were conducted in this paper, the first experiment was to examine
the accuracy of the proposed method by simulating various SUT using simulated
resistor, inductor, and capacitor (RLC) network. The next experiment was to
detect incipient stator faults such as turn to turn faults in an induction
motor. This proposed method measures the impedance of the stator winding of an
induction motor to identify abnormalities. In addition, this method allows for
an accurate in-circuit impedance measurement without the influence of motor
load and frequency changes as well as faults such as bearing and rotor faults.
