Machines, systems, and their components are subject to wear and tear and must be serviced, repaired, or replaced at regular intervals. These measures are usually carried out on the basis of a maintenance plan. But when is the right time for servicing or replacement?
In this blog article, we look at condition monitoring of machine bearings in explosion-hazardous areas and its advantages in maintenance planning. You will also learn how the KCD2-VR4-Ex1 isolated barrier from Pepperl+Fuchs makes predictive maintenance in explosion-hazardous areas easier and more efficient.

Condition Monitoring Enables Predictive Maintenance

A maintenance concept encompasses the scheduling and organizational planning of inspections, servicing, and repairs. Such a plan is essential for maintaining the functionality and safe operation of machines and systems in order to avoid failures and unplanned downtime. Due to the growing use of intelligent field devices that transmit signal data to the control level in real time, maintenance teams can now detect both short-term and long-term changes—for example, in the vibration behavior of rotating machines. As a result, condition-based and predictive maintenance are becoming an increasing priority for maintenance planners.

In an interval-based maintenance plan, for example, plain or roller bearings are often replaced before the end of their service life. This results in unnecessary costs for labor, plant downtime, and spare parts procurement, as they are replaced more often than necessary.
If, on the other hand, a bearing is not replaced before failure at the end of its service life, it can cause damage to the system, but also to hazards for people and the environment, and to increased, unplanned downtimes.

In order to optimize plant availability and operating costs, the timing of maintenance, repair, or replacement should be determined as precisely as possible. During condition monitoring of machines and plants, suitable physical parameters are continuously recorded and evaluated in real time. These provide information about the necessity and timing of servicing or replacement.

Advantages of Condition Monitoring and Predictive Maintenance:

• Plant availability is increased because impending failures of plant components are detected in advance and unplanned downtimes are avoided.
• Damage resulting from malfunctions of defective plant components (e.g., bearings on rotating shafts) is avoided, as are the resulting hazards to people and the environment.
• The operating costs of systems can be reduced if maintenance, repairs, and replacements are event-driven, which means only carried out when actually necessary.

Condition Monitoring of Machine Bearings

Condition monitoring of bearings in rotating machines such as turbines, generators, or compressors is extremely important. For this purpose, the vibrations of the mechanical components are measured using special sensors on the shaft bearings and the shaft itself. These are vibrations that occur in the bearings, for example. Typical patterns provide information about the condition of the bearings. The measured vibrations include a substantial share of high frequencies, which must be transmitted from the field to the evaluation unit without distortion. The cut-off frequency of the module must therefore be high enough to ensure that the measured vibration is not significantly attenuated. If the part of the system to be monitored is located in an explosion-hazardous area, explosion protection must be ensured along the data transmission path.

Isolated Barrier for Signal Transmission of Vibration Measurements in Explosion-Hazardous Areas

The 1-channel KCD2-VR4-Ex1 isolated barrier from Pepperl+Fuchs enables the transmission of high-frequency sensor signals from explosion-hazardous areas to control and monitoring systems in non-hazardous areas. The device supports all common sensors for condition monitoring, such as vibration sensors, displacement probes, acceleration sensors, seismic sensors, or magnetic pick-up sensors. By extending the transmission range, sensors without their own voltage or power supply can also be used. The voltage repeater therefore enables modern and efficient condition monitoring and predictive servicing for the protection of machines and systems in explosion-hazardous areas. The device has international certifications such as ATEX, IECEx, UL, and CCC. The galvanic isolation and the high cut-off frequency of 20 kHz (-1 dB) ensure high transmission quality.

The KCD2-VR4-Ex1 voltage repeater is suitable for safety-related applications up to SIL 2 (SC 3) Ed2 according to IEC/EN 61508 and is TÜV-certified accordingly. The low power dissipation allows use in a temperature range from -40 °C to 70 °C (-40 °F to 158 °F). DIP switches on the front support easy configuration and allow the selected settings to be identified at any time, even when installed.

More Information

• KCD2-VR4-Ex1 voltage repeater
• Predictive Maintenance Made Easy: Isolated Barrier for Vibration Monitoring
• Vibration sensors for explosion-hazardous areas