Diagnostics of electric motors on the basis of a current spectral analysis
Complex of works on audit of operating conditions of an electric and mechanical part of electric motors, mechanical devices connected with them on the basis of processing results of monitoring of a currents and the supplied voltages
Now at the industrial enterprises and in modern office buildings the park of electric motors consumes from 40 up to 70 % of the paid electric power.
Operation of electric motors being a unsatisfactory technical condition brings to:
- To the direct financial losses, connected with not predicted failure of the equipment and caused by this infringement of technological process;
- To significant (up to 3-5 %) to the indirect unproductive expenses of the electric power caused by the increased power consumption (at the same useful power).
Methods applied now is Vibe-diagnostic, or one must to remove of the engine from work (measurement of resistance of isolation, resistance of windings, etc.)
The offered technique is based on that fact, that any indignations in work of an electric and/or mechanical part of the electric motor and the device connected with it lead to changes of a stator-rotor magnetic field and, hence, to weak modulation of a current consumed by the electric motor.
Performance of monitoring of a current of the working motor during a short interval of time and the subsequent special spectral analysis of the received data allows to determine presence of following damages:
- Short circuits of stator windings ;
- Damages of bearings;
- Misalignment of shaft of the motor and its mechanical load;
- Increased eccentricity a rotor (static and/or dynamic);
- Defects of a rotor;
- Rotor rub;
- Defects of a mechanical part of the devices connected to the electric motor.
Definition of a degree of damages is made on gradation "Damages are absent" - "Damages are found out" - "Critical Damages Are found out". At carrying out of repeated measurements on the given equipment the database is formed, allowing to trace changes of development of damages in time, that enables to plan removing the equipment in repair.
Performance of monitoring of the voltage suppplied to the electric motor allows to determine its asymmetry, presence of the harmonic components and impulses of overvoltages (that is possible at work with frequency regulators of speed of rotation) - i.e. those factors which directly influence for the term of service and profitability of work of the motor.
Measurements can be executed as directly on the electric motor (without any infringement of a mode of its work), and in an panel of its supply.