There are many different reasons to consider and implement an online vibration system. Some of the key reasons are:
- The equipment is critical to production.
- The equipment has a long repair time.
- The parts for the equipment have a long lead time.
- The equipment is not easy to access.
- The equipment is in a remote location.
- Equipment failure could endanger the environment or people.
Online systems like the CORTEX by BETAVIB allows not only vibration to be monitored but also many additional parameters (such as speed, temperature, pressure, and flow, to list just a few), all of which can also be monitored and recorded. In addition, a customized overview can also be created to allow anyone to quickly monitor the health of the equipment using red, yellow, and green alarms that will indicate if an issue is present.
The CORTEX Monitoring System (CMS) is a cost-effective, scalable solution, dedicated to the prediction of asset failure and the prevention of catastrophic failures and costly repairs. This innovative system will help you optimize your performance by monitoring the condition of your valuable assets with highly accurate diagnostic tools.
by Yolanda Lopez
With the proliferation of online monitoring systems utilizing permanently mounted sensors, users will need to beware of “direction sensitive” vibration and possible sudden unexpected failure due to insufficient data. The thought of insufficient data may seem incredible when thinking of constantly monitored equipment, but consider the all too common (imho) practice of uni-directional (one direction) monitoring of machine trains.
Many installations, due to initial cost, are mounting a single vibration sensor at each bearing. While this may be sufficient for most equipment trains, most of the time, it will certainly not be sufficient for all equipment trains all of the time. Although I don’t have hard data available, if I were to make a statement based on personal experience, and anecdotal evidence from other practitioners, my statement would be something like this: “80% of horizontal equipment could be pretty well monitored by sensors mounted at the horizontal radial position on each bearing.” I say pretty well monitored because I just can’t bring myself (as an analyst) to be completely satisfied without the vertical and axial data.
This setup would catch virtually all unbalance and roller bearing faults (excluding thrust bearings), some to most misalignment faults and a sprinkling of others. I use the word “catch”, to mean it would give an indication of a developing problem. Accurate diagnosis of unbalance, misalignment, bent shaft, and even looseness in many cases (as well as a host of other possible faults) would require more data.
If the online vibration program manager takes these facts into account and governs the program accordingly, they should be pretty successful. If they add to the online program a “full battery” vibration survey, maybe semi-annually, just to catch the less common, but possibly very destructive defects that could develop undetected by the uni-directional monitoring, they would most likely be very successful.
What could be so destructive and yet be completely undetected by the uni-directional sensors? The Big R for one, Resonance. Resonance is often extremely directional. Consider a case history LUDECA co-published with one of our customers in the December 2012 Wastewater Processing magazine:
In the table below (Figure 1), the 1× amplitudes are displayed. I have hidden all but the vertical data, as though it were monitored only by vertical sensors.
Everything is wonderful right? Look at the motor outboard vertical, only 0.00384 inches per second—very impressive. Of course, at this point you are thinking “he is setting me up for something” and you are correct. Even though most anyone would love to have these amplitudes on virtually any machine, this particular machine was tearing itself apart with vibration!
We will give the reader a little more data, just to help add emphasis to the directional nature of a resonance. We will add the axial data to our table in Figure 2:
Still very, very good… so far. Now look at Figure 3, with the addition of the horizontal data.
The motor outboard horizontal amplitude is 162 times the amplitude of the motor outboard vertical! What if the user had only vertically mounted sensors? What about vertical with the added information of axial? You may be thinking “if I had only horizontal sensors, I would have been ok”, and for sure you would have been better off than having only vertical. You would at least have known you had a problem, but you would not have known what that problem actually was. You would likely have assumed the vertical and axial are probably vibrating badly too. Hopefully you would have verified the vibration in the other directions. As it was, the user had data from all directions and a simple glance told the analyst with a high degree of confidence what the problem was. Resonance is almost alone in creating that kind of directional disparity.
To reiterate, the online vibration program manager should be successful if they take into account the fact of limited data and supplement the online program with a “full battery” vibration survey at a cost effective interval, just to catch the less common, but possibly very destructive defects that could be developing undetected by uni-directional monitoring.
by Mike Fitch CRL
In today’s modern world information is found all around us and it is available at the simple push of a button; 24/7/365. Machine condition monitoring systems (online systems) have been around for quite a while, but they have typically been reserved for the most critical and most expensive machines at a facility. These critical assets typically comprise of a small number of the total assets at most manufacturing plants. The majority of machines fall under the walk around monitoring approach. If a condition monitoring program is being conducted at a world class level then each machine is being tested monthly, however at most manufacturing facilities manpower constraints restrict monitoring to quarterly or in some cases once or twice a year. Machines which have been historically confined to a walk around type programs can now be monitored successfully using an online system. These systems can monitor and trend vibration levels as well as monitor and trend ultrasound and temperature. The online systems can be configured to deliver a machines alarm status directly to the plant process control system. This allows the machine operator to take the necessary corrective actions. The alarm status can also be delivered to a maintenance supervisor via cell phone message or by email. Using online systems to monitoring the health status of your process equipment will allow the identification of problems early with minimal manpower so that catastrophic failures can be prevented which ultimately leads to less machine downtime for repairs and increased cost savings.
by Dave Leach CRL CMRT CMRP
New portable and online-monitoring systems help extend the value of vibration monitoring into the heaviest of industrial operations. Here’s a look at how users avoided serious motor failure in mining and detected a critical bearing failure in paper-pulp production by using the right vibration products at the right moment.
Case Study #1:
A Phosphate mine is garnering big returns by monitoring numerous pieces of processing equipment with online solutions from LUDECA. The mills use several low-cost VIBNODE online systems. The VIBNODE is a comprehensive entry-level online monitoring system that allows the end-user to access customized spectrums and time waveforms from a remote location. The system will notify the end-user via email or text message when the vibration level exceeds an alarm band.
The new monitoring system has helped the mine’s vibration group catch several problems with a newly rebuilt drive motor. The waveform showed a fuzzy amplitude modulation that increased and decreased with every RPM. A look at the acceleration spectrum indicated a large amount of high-frequency noise well over 1g. Upon inspection, several internal retaining bolts were found to be backing out and contacting the frame of the motor rotor. The bolts were tightened to torque specifications, which was believed to have solved the problem. A week later, however, the problem reemerged as the bolts had once again backed out and began to rub. The bolts were again torqued to specification, but this time with an application of threadlocker, which held the bolts in place.
Had this problem not been identified by the fuzzy waveform and a high-frequency acceleration band alarm from the VIBNODE system, the errant bolts would have quickly eaten into the motor rotor and caused a catastrophic motor failure. The motor rebuild or replacement is valued at well over $100,000. And losses to production would have been many more times this amount.
Case Study #2:
Low-speed equipment turning below 40 RPM is often difficult to analyze because of the low energy it produces. If there is not much energy, there is often not much to see. For this reason, the dynamic range of a vibration analyzer/data collector and its signal-processing quality become critical for low-speed machine analysis. Recently, a pulp mill using a VIBXPERT analyzer from Ludeca took a spectrum and time waveform on a slow-speed 35 RPM roll. The VIBXPERT is a portable, lightweight, 2-channel, FFT data collector/vibration analyzer for monitoring and diagnosis of machine conditions. As a data collector, VIBXPERT records all forms of machine vibrations, bearing conditions, process data and visual-inspection information.
Because of the dynamic range of the VIBXPERT, the mill’s maintenance technicians were able to see a repeating pattern in the time waveform. The recurring pattern was present for every RPM, and would increase slightly, then disappear for about three-quarters of the roll’s revolution. A delta cursor was placed on the repeating pattern and the source frequency was 420 CPM. This worked out to be the frequency of the inner race. A 25,000-line spectrum was also collected with a bandwidth of 7.5 CPM per line of resolution. The amplitude was very low below 0.0008 inches per second, yet a definite harmonic pattern appeared. The main harmonic pattern was at 420 CPM, with each peak having another underlying pattern of 35 CPM sidebands. The frequencies represented the inner race and roll RPM. Had this data been taken using a conventional spectrum with a resolution of 6400 lines or even 12,800 lines, this low-frequency/low-energy event would have looked like a spectrum ski slope and been ignored.
Upon removal of the bearing, a crack in the inner race was plainly visible. There was evidence the inner race had begun to walk around the shaft. If the bearing had been left in service it would have damaged the shaft and required that both the shaft and bearing be replaced. Instead, only a minimal two-hour shutdown was required to replace the bearing. Thanks to early detection, the cost of replacing a roll was averted, as well as saving the eight or more hours of lost production that a roll replacement would have required.
by Greg Lee
When wiring an online remote monitoring system or accelerometers into a termination box/switch box, it is a good practice to run the cables in flexible or rigid conduit. After the fact, it is highly recommended to label both ends of each cable with its respective measurement location. If ferrule tags are not available for labeling, colored electrical tape can be used and marked with an indelible marker.
If you have an online monitoring system, it is recommended to send data (overall vibration), alarm values and machine status to your process control system or DCS. The data can be sent using MODBUS TCP/IP or MODBUS RTU. This way, there is no need to run extra wires into your control system.
by Alex Nino CRL
As with most projects, communication is the vital key for a successful completion.
When you purchase an online remote monitoring system, such as a VIBNODE or VIBROWEB, there are other things to consider besides the purchase of the equipment itself. Factors to consider include: Deciding who will install the hardware; deciding how communication from the devices to the customer’s or plant’s network will occur; determining whether the equipment or asset to be monitored is at a remote location or situated in house; identifying any safety requirements for installing or handling the condition monitoring equipment; when and how to bring the systems online, etc.
In order to guarantee the successful installation and project completion of an online remote monitoring system, here are five crucial steps to follow:
1. Appoint a project manager. It can be an employee at your facility, a person at the corporate office, or a LUDECA engineer who has managed projects before and can assist you with communication and timelines.
2. Install the hardware. If a turn-key installation is not possible, contact your facility’s maintenance department and electricians to assist with installing the hardware.
3. Optimize Communication. Contact your company’s IT department in the beginning stages of the project. Get them involved as early as possible. Contact your health and safety department to ensure there are no problems with installing your condition monitoring hardware at the desired location.
4. Involve Operations. Contact your operations and maintenance department to establish a timeline for when the equipment you wish to monitor can be shut down for sensor and cable installation. Most facilities will perform this work during a planned shut down or will schedule a temporary shut down for installation to occur.
5. Start-Up & Commissioning. Contact LUDECA to schedule the commissioning of the systems. LUDECA can send a certified engineer who is highly trained in commissioning and operating online systems and is also a certified vibration analyst.
by Alex Nino CRL