Automatic Rotor Tester

The Rotor tester uses the principle of electrical and magnetic effects caused by the circulation of induced currents into the bars of a rotor, which is made to turn at a constant speed, with in a magnetic field produced by a permanent magnet. The induced magnetic field produced by permanent magnet, acts on one slot at a time. The direction of magnetic field is such that the turns of a moving rotor cut the lines of force normally.
The induced currents, which are proportional to the field intensity (distance of magnet from the rotor, on the speed of rotation constant) & on the rotor characteristics, produce magnetic fields, the symmetry of which enable a clear observation of the turns in the short-circuited condition. A fixed probe subjected to the magnetic fields produced by the rotor under test, provides the signals, which after being amplified, are applied to the monitor.
The synchronized sinusoidal wave pattern from the rotor bars is displayed on the monitor screen. The waveform identifies typically occurring faults in the rotor bars & there is a distant correlation between the result of the inductive test of the rotor bars & the starting torque of a motor.