As critical manufacturing processes become more complex, so does the motor control system behind them. As a result, it's more important than ever to keep these critical assets running at peak performance, as not only are equipment failures costly, but also lost production costs from waiting for replacement parts or motor rewinding services can be high. Since motor failure can lead to a variety of electrical and mechanical issues, both of these must be considered when performing any troubleshooting procedure. In addition, by prioritizing workloads and performing regular preventative maintenance, facilities can better reduce the likelihood of unexpected motor failures caused by normal system operating stress.
Below, we describe four basic steps to prevent such premature failure of electric motors.
The first and most important step in preventing motor failures is to capture initial asset data. This includes the specifications of the machine, the performance tolerance range, and the operating conditions at the time of installation. With this information, it is possible to establish a baseline of how the motor will operate, and any deviations from the original installation can be more easily detected when regular preventive inspections are carried out.
Not only that, but it also allows people to spot potential problems before improper installation causes motor failure. While all mechanical equipment is subject to wear and tear, improper installation can accelerate the wear process and cause it to deteriorate faster. Therefore, proper installation lays the foundation for the service life of the motor, and sometimes even extends the life of the motor.
Before turning on the motor on a working day, take care to check if there are any of the following problems:
Shaft voltage:Exceeding the insulating capacity of the bearing grease can cause flashover currents to occur in the outer bearings.
Pipeline strain:The forces and stresses acting on the rest of the motor may be transmitted backwards into the machine.
Soft feet:The motor mounting feet are uneven.
Once all the motor data has been captured, the next step will be to develop a regular preventative maintenance plan that will be used not only for maintenance but also to track the health of all the motors in the facility. In each round of maintenance, get into the Xi of comparing new measurements to initial motor specifications and tolerances to identify potential anomalies. Additionally, consider adding thermal imaging to your test regimen to determine the heat output of motors and other related assets. Such tools can instantly verify that they are running too hot or too cold than usual, which could indicate an issue that requires immediate attention.
But regardless of strict and timely maintenance, some mechanical problems can still arise because time will always wear out everything eventually. That being said, thanks to regular maintenance and addressing mechanical issues early before they become bigger problems, motors will last longer, eliminating the need for long-term replacements.
Some of these common mechanical problems include:
Bearing wear:Bearing wear occurs when surfaces slide against each other due to insufficient lubrication to keep them separated.
Misalignment:This usually means that the motor drive shaft is not perfectly aligned with the load.
Loose shaft:It is caused by too large a gap between the fixed element and the rotating element inside the motor.
Shaft unbalance:The center of the rotating part is not entirely on its axis of rotation.
Many failures caused by mechanical problems usually manifest first as vibration. As a result, integrating a vibration sensor system into an operator's toolset can help identify many of these issues before they cause motor failure.
When performing preventative maintenance, save all thermal images and measurements acquired during this process, as they can be used to create a baseline of the performance of your facility's motor assets. Any change in the trend line that exceeds 10% to 20% must be investigated immediately to determine the root cause. Most likely, these percentage changes in the trend line may not apply to your specific asset, so a more appropriate number needs to be determined based on the performance of the system or the importance of the asset.
Since a variable frequency drive takes one waveform and converts it to another, establishing a baseline for a running motor will allow you to see when the output has changed.
The use of a motor drive analyzer allows for rapid detection and diagnosis of VFD-related issues, typically including:
Operational overload. Sigma currents or stray currents circulating in a motor system.
Reflections of the drive output PWM signal caused by an impedance mismatch between the load and the power supply.
Once the baseline is established, continue to track and document the results of your measurements on a regular basis, as you can use the collected data to create an archive. In addition, it creates trend analysis, making it easier for other operators to notice changes in motor condition over time.
Proper trend analysis helps diagnose a variety of power quality-based issues, including:
Transient voltage or electrical energy surge caused by a sudden release of energy.
Harmonic distortion caused by a poor additional high-frequency current source or an AC voltage source supplying power to the motor windings.
Voltage and current imbalances due to differences between phase angles or voltage amplitudes.
Recognizing the early signs of movement problems and nipped them in the bud is key to avoiding movement failures. By following the steps above, facilities can better identify potential problems before they develop into larger problems and avoid the cost of asset replacement or downtime. Once your machinery has finally stood the test of time, hiring a mechanical engineering and service provider is your best option for revitalizing your assets and sourcing the products you need, such as engine grease or natural ester transformer oil