Motor monitor System and Motor Electricity Diagnostics

About motor diagnostics in general:

We can say that for the propelling of every rotor, through the engines and clutches an electric motor is responsible. These machines are counted among the most widespread equipments. The problem is that the techniques applied so far (ex. vibration diagnostics) could not really define the errors inside the electric motors; fine localisation mainly in the case of electric errors was not unambiguous.
Providing that some of the electric elements of the rotor get damaged electrically, this will result in the formation of an unequally distributed magnetic field. Consequently, we have to expect bigger asymmetrical mechanical load of certain components which will also be considerably alternating in time. In the case of motors at bigger absorption of energy a smaller mechanic achievement can be obtained, in the case of generators the delivered electrical energy decreases at the same mechanical drive. The greater losses deriving from the decrease of efficiency change into heat, thus the thermal loading of the components increase further on. The application of motor electricity diagnostics is justified by the fact that both the mechanically generated and electrical vibrations are present at the same time on the electric machine, so in order to perform a vibration analysis both these and their interactions must be taken into consideration.

About the motor monitoring system in general:

The asynchronous motors are the most widespread machines of the industry. The diagnostic methods generally applied so far were not suitable for reliable identification certain errors and for judging their degree's, mainly not of those emerging on the electrical side. Such errors are the crack or failure of the amperage ring or the squirrel-cage motor, the increased resistance of connections unevenness of the armature-gap. The motor monitoring system is an expert examination system that is suitable for detection and accurate recognition of electromotor failure with the aid of its knowledge base containing its huge amount of experience in motor examination without intervention in operation and by examining the motors' spectra.

Malfunction occurring on the rotors:

• electromagnetic unhomogeneity
• loosened block of blades
• the breaking of rotor bars
• loosened rotor bars
• breaking of the discharge rings and squirrel-cages
• aberration of the slip rings and brushes
• pollution (deposition, oxidation)
• short circuit (between the ground and the rings)
• the errors of the commutator
• the breaking and short circuit of the segments

Malfunction occurring on the components:

• short circuit of the winding between phase and phase, winding and winding, winding and ground
• loosened winding
• asymmetrical electromagnetic field
• unbalanced tension
• contact error in the joints

In general about measuring electrical parameters:

For maintaining electric motors recording such parameters as measuring feed current per phases, the current drain of the motor during clearance as well as detecting certain resistances is essential. Beyond the above listed the necessity of the equipments' examination from contact protection point of view does not call for any explanation.

The Kalkon Ltd. performs motor electricity analyses with CSi 2120-A2 UltraSpec electricity measuring device, with its dependent expert system, with UNILAP ISO insulation indicator as well as with LH 1050 devices.