Electrical impact analysis and electromotor power are the most important and fundamental components in the situation monitoring services. This analysis of the entire electrical system comprises the inputs of the power switch in the 10 kV, 6 kV, 600 volts and 400 volts panels and ends with the smallest parts of the motor. The drive system, cables, stator winding, rotor cage (for cage rotors) and rotor winding (for twisted rotors) will all be monitored and faults that are not detectable by other tools prior to damage. This inspection will be identified at a very early stage. Defects such as fracture or crack in the rotor loads, improper connection of the load rotor to the End Ring, defects in the core, aerial distance, lack of centralization of the rotor, permanent or instantaneous unwanted harmonics in voltage and current, rectification of the rectifier system and drive inverter, drive drive And leakage current, partial discharge in susceptible coils, torsional vibrations, all are defects, although the electric motor will continue to operate for a limited time under stress without any external effects but will suddenly stop causing extensive damage. Interestingly, all of these defects can be identified prior to the damage by a unique electrical impact analysis technique. In this technique, the probable failures in the motor circuit are divided into 7 zones (Fault Zone) which are:
– Stator
– Rotor
– Air distance
– Insulation
– Power circuit
– Drive
– Power quality
The technique of analyzing electrical effects is low-risk and low-cost. With this technique we can detect defects such as fracture and rotation of the rotor rods, out of dynamic and static center, bearing failure, impedance, non-alignment, foundation locking and mechanical and electrical defects of the stator. Electrical impact analysis is a process in which voltage and current signals, current and leakage voltages and partial discharge signals are collected for various fault detection and eradication and stored in the reference database. The test result is compared with the initial tests that are called immediately to indicate any problems with the device. Electrical impact analysis systems are an online electrical impact analysis that does not require the machine to be removed from the circuit and the machine is operating. Below we will introduce the dynamic monitoring services of the Aria industry in the specialized field of electrical impact analysis.
All of the above can be remedied with minor modifications to the site or minor repairs before major damage is timely diagnosed. Otherwise burning of the coil, insulation, replacement of the core, major rotor repairs and so on would be unavoidable. The following steps are taken to analyze the condition of the engine and generator in the fault diagnosis procedure.
1- Analyzing information and estimating some useful information by smart software
2- Analyze the motor behavior in terms of rotor, stator, kernel, etc. using the permissible range for each part.
3. Determine the health status of the equipment under test and make a decision regarding it
Tests and services performed by Pouya Peishaneh Sanat Aria Company are as follows:
1- The set of electrical tests, sometimes referred to as the Comprehensive Electrical CM, is performed under the ESA format for ESA analysis of two types of tests on the engine.
These tests, while analyzing the current state of the electromotor, predict with great accuracy the start of defect formation in each of the engine elements. Also recorded electromotor information is kept as an equipment identifier which is referred to as “electrical signature” in Condition Monitoring. This information can be used as a basis for comparison in subsequent periodic tests. Changing any of the parameters mentioned in the two measurement intervals will provide a very good component of the engine’s condition to prevent severe damage and prolonged stoppages, if necessary, in the early stages.
Source of error in induction motors
Standard and Overhaul Stage Tests These tests are complementary to the flow analysis tests and the Electromotor Status Analysis Base, described below. Usually, every visit to an electric motor will even be performed on a case-by-case basis in order to provide a complete picture of the electric motor behavior. In the field of preventive maintenance and standard tests, the company, having many years of experience in the field of electromotor testing, has complete expertise in testing standards, analyzing the results and advanced equipments and modern equipments in this field.
Stator faults
Defects of the rotor
Air gap faults
Power quality defects
Errors related to the drive system
Eccentricity
Table 13- Mix eccentricity results
Mix Eccentricity
Electromotor Flow Analysis Technique
Arya Pouyan Pishat Sanat Co., with its ESA Experts and extensive industry experience in this field, is fully prepared to offer its best in service, on a case-by-case basis, as well as standard preventive maintenance tests.
Health status check with partial discharge method online
PD test conditions ONLINE and include: breakdown breakdown analysis in the middle layer of insulation, outer layer of insulator contact with the stator core, inner layer of strand and coil contact insulation, weakness in coils, weakness in lead, insulation dryness detection, detection Corona semiconductor insulator failure in coil arm, contamination, wedge problems and other defects that cause partial discharge. All test data were extracted using HFCT mounted on 3 engine phases. HFCTs loop around the power input cable of the motor or from the switch and detect partial discharge signals. This test is for MV electric machines only and is related to the MV electromotors. It answers the question of whether or not the electromotor needs overhead. The test curves are presented along with the general conclusions of the test.
U-phase partial discharge time curve with synchronous signal
3D phase U-phase PRPD curve
Number of pulses per second relative to their size in mv in U phase
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