With the innovation of industrial technology, the frequency conversion motor system is more and more widely used, and its own technology is also more and more complex. Unexpected downtime will bring unpredictable maintenance costs and economic losses. How to ensure the healthy and efficient operation of the motor system has become the most concerned issue for operation and maintenance engineers.
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Since motor failures are often related to equipment failures and power problems, equipment and circuit parameters are also checked when troubleshooting motor failures. Technical and operations experts often develop preventive maintenance plans to monitor the working condition of circuits, equipment, and motors in the event of failure. How to develop a sound maintenance plan? We have a four-step suggestion for your reference:
1
When the motor is initially installed, record the measured values of the operating parameters
The first step of preventive maintenance is to record and save the parameters of the equipment under the initial working conditions, including the working environment, equipment technical indicators, allowable errors, etc. The purpose of this step is to save the reference value of the best state of the equipment. In future maintenance work, potential problems can be found only by comparing the difference between the measured value and the reference value.
Any hardware device will be worn out during use, but the best installation method and use conditions can greatly extend the use time of the device. Before actually putting it into use, pay attention to check whether there are these problems:
Motor mounting feet: whether the motor mounting feet are even
External force transmission: Be careful to transmit the force acting on other equipment to the motor
Shaft Voltage: When the voltage on the motor shaft exceeds the insulating capacity of the bearing, current flows through the bearing
2
Standardize preventive maintenance cycles and complete tests on time
After obtaining the initial working parameters, we have the most basic reference value. In the follow-up operation and maintenance work, one of the indispensable tools is an infrared thermal imager, which helps us to quickly observe the temperature distribution of motors and other equipment. It is recommended that you use the Fluke Ti480Pro thermal imaging camera to quickly observe whether the temperature of the device is too high or too low, so that we can investigate potential problems and failure causes in more depth.
Thermal imaging cameras (such as Fluke Ti 480Pro) help us find problems early and eliminate hidden dangers
With the passage of time, equipment will inevitably wear out or even fail. The purpose of preventive maintenance is to replace worn parts in time to prevent more parts from being damaged and causing economic losses. Common device problems include:
Misalignment: Misalignment between the motor drive shaft and the load
Unbalanced: The center of the rotor is not on the shaft
Loose shaft: The gap between the rotor and stator inside the motor is too large
Bearing wear: surfaces sliding against each other
3
Store and record the measured value of each maintenance for the observation of equipment status
Keep the equipment parameters and thermal images of each test. If you observe that these values change by more than 10%-20%, you must pay attention and examine the reasons for these changes in detail. Some devices or components are subject to stricter variation restrictions, depending on the situation.
The inverter has an input end and an output end, and is a key component in the operation and maintenance work, which requires special attention. Measure and analyze related problems with a true rms multimeter and variable frequency motor drive analyzer. Fluke MDA550III provides a guided menu that can automatically and efficiently analyze inverter-related motor-related faults, and can generate test reports for users to save test results. Using it, you can quickly test the following problems:
Check the drive output, focusing on V/F in case the motor heats up or doesn't have enough torque
Sigma Current: Stray current circulating in the system
Shaft voltage: timely detection of the risk of excessive shaft voltage
In addition to motor drive analyzers, handheld oscilloscopes,
Such as the Fluke120B series, can also easily help you test waveforms to decide what maintenance action to take.
4
Focus on trend changes and analyze the reasons for changes
Once a reference benchmark is established, regular testing is done, and test results are recorded, we can then perform trend analysis based on these. A reasonable trend analysis strategy can help us find many problems about power quality, such as:
Transient Voltages: Transient voltages can cause surges in electrical energy
Voltage and current imbalance: voltage magnitude or phase difference
Harmonic Distortion: High-frequency AC voltage or current input to the motor windings
Active maintenance instead of passive maintenance
When service engineers and technicians are equipped with the proper tools, expertise and basic data, we can identify potential problems with motor failures before they become serious. Following the four steps described above will help us catch motor problems before they fail, which will significantly avoid equipment replacement and downtime.
