Today’s webinar is titled “MCSA: Motor Current Signature Analysis” What does MCSA tell us? Many people have different terminology when it comes to testing a motor system. We have a power supply, cabling, electric motor, and load in any field. There are mechanical and electrical elements to a motor system. If we want to test the engine, it doesn’t matter if it breakdown mechanically or electrically. So, this type of technology comes in on its own because it covers both electrical and mechanical.
The presenter then displayed a graph of motor failure studies in several industries. When it comes to motor issues, we may divide them into two categories—problems with the electrical and mechanical systems. The automatic has the more significant percentage of this problem. The electrical has a 25 to 35% of this problem, and it has no warning signs. Meanwhile, the machine has 65 to 75% warning signs. According to the IEEE in 1983. Bearing failure accounted for 44% of all losses. The stator gets a quarter of the total. Other failures account for 22% of total delinquencies, whereas the rotor accounts for 8%. In 1984, according to EPRI. The bearing was lowered by 41%. The percentage has risen to 36 percent. Other failures account for 14% and 9% of the rotor, respectively. The IEEE 1995 Petroleum Industry is a decade old. The bearing increases by 51%. The exterior problem and the stator are roughly 16 percent. At 10%, there is an unknown problem—5% for the rotor and 2% for the shaft.
The presenter then displayed a graph of the Insulation life curve. So when we look at the insulation of the motor, we can see that over some time, the insulation deteriorates at the point of the supply voltages is more significant than insulation integrity then we have a shortage in the windings, which leads to burning up and complete failure of the motor. That will be the time that the engine will fail, so we have to monitor this insulation to identify when it is going to die. Next is we have another motor, let us say that the other motor failure is half of the first motor. We looked at the different factors that would lead us to half-life expectancy. Static testing will identify where the insulation is at a particular point or its level. Next is dynamic testing would be performed with the motor running in its typical environment and load condition. Equipment connects directly to the load side of low-voltage engines or in the low-voltage cabinet of medium- and high-voltage motors collecting voltage and current information.
Dynamic testing overview the ability to find power condition, motor, and load-related issues while running under normal conditions. We measure, analyze and trend the currents and voltages of the motor-load system. It gives to the root cause analysis. This is important. We have a lot of symptoms that the electric motor might show that may not have any critical bearing at that time but might add stress to the engine, which leads to a potential breakdown of the insulation, which helps us define the problems that we need to know. It involves mechanical issues, bearing problems, rotor bar issues, cavitation, and eccentricity. It is very similar to the vibration analysis.
Complete System Analysis is composed of power supply, motor, and load. Dynamic electrical testing evaluates each component of the electromechanical system and identifies environmental factors that will accelerate insulations degradation. Static testing directly considers the integrity of the insulation, identifies insulation weakness, and predicts electrical insulations failures. Next is what values do online measure and trends. First is the power quality. It measures the voltage level and unbalances harmonics distortion, total distortion, power, and harmonics. The second is machine performance. It measures the influential service factor, load, operating conditions, efficiency, and payback period. The third is the current. It measures the current level and the current unbalance. Fourth is the spectrum. It measures the rotor bar and demodulated spectra. Fifth is the torque load/mechanical it measures the torque ripple and torque spectra.