What is Vibration Sensoring?
- Also known as Vibration Monitoring
- Machine Condition Monitoring/Product Testing/Quality Assurance
Vibration sensoring, also known as vibration monitoring, is a great way to determine the condition of machinery. While it may seem surprising, abnormal vibration is a telltale indicator of problems with a machine. The earlier you can detect those problems, the better; machine failure can be very expensive to deal with. It’s costly in more than just monetary terms – machine failure leads to losses in money, productivity, and time.
And it does more than just tell maintenance staff that there’s a problem. Vibration monitoring can even alert staff to the location and type of problem the machine is having.
In the end, vibration sensoring allows companies to detect machinery issues early and prevent machine failure, thus saving them money and increasing efficiency.
Why do it?
Some plants operate on what is known as a “run to failure” maintenance strategy. Basically, they don’t take action until the last minute, when machinery begins to fail. While this is pretty commonplace, it is not very cost-efficient or productive. Losses are high due to this strategy.
There is also calendar-based, or preventive, maintenance. Unlike “run to failure” maintenance, this type schedules action no matter the equipment’s condition. This can lead to unnecessary equipment repairs, and higher production costs.
What makes vibration sensoring different is that it is under the umbrella of condition-based maintenance. With condition-based maintenance, plant owners save time and money. Using techniques like vibration sensoring means plant owners don’t have to tear down equipment to find out what condition it’s in. Furthermore, unlike calendar-based maintenance, repairs are only scheduled when needed, saving plant owners money.
Benefits of Vibration Monitoring:
There are many benefits and advantages to vibration sensoring. Plant owners do it because it’s cost-efficient, saves them time, increases productivity, and decreases downtime, among other great benefits.
- Predictability. Allows staff time to schedule needed repairs and get parts.
- Safety. Take faulty equipment offline before a hazardous condition happens.
- Revenue. Have fewer unexpected, serious failures, which helps prevent production stoppages that cut into your bottom line.
- Increased maintenance intervals. Extend equipment life and don’t waste money on repairs you don’t need. Only repair when necessary.
- Reliability. Have fewer unexpected, catastrophic failures due to anticipation of problem areas before failure.
- Peace of mind. Build confidence in budgeting, maintenance schedules, and productivity estimates.
How does a vibration sensor work? How is vibration measured?
Vibration sensors measure, display, and analyze a machine’s linear velocity (speed), vibration displacement, and vibration acceleration.
It’s important to note that there are different types of vibration sensors:
- Vibration sensors – Packaged as raw sensors.
- Vibration transducers – More complex sensors that output a voltage or current signal.
- Vibration transmitters – Sensors packaged with the means (i.e., integral signal conditioners) to transmit a more complex output.
- Vibration switches – Use an integral sensor to make/break contact upon detection of certain vibration levels.
Note that accelerometers are the most commonly used types of vibration sensors. Accelerometers are sensors that produce an electrical signal proportional to the acceleration of the vibrating component the accelerometer is attached to.
How quickly is the velocity of the equipment changing? That’s the acceleration of the vibrating component.
Here’s how vibration monitoring sensors generally work:
- Attach the vibration sensor to the equipment you want to measure.
- Identify vibration peaks as they relate to a source component on the machine.
- Look for patterns in the data based on vibration rules.
- Measure the amplitude of the vibration peak to determine the severity of the fault.
Once you determine fault and severity of the problem, repairs can be recommended and started.
How to Mount an Accelerometer the Right Way
The only way to get accurate measurements in a safe manner is to mount the vibration sensor and utilize it correctly. The steps below detail how to do just that.
Mount it as Closely as Possible to the Bearings
When a doctor listens to your heartbeat with a stethoscope, they need to put the instrument in the right place. Otherwise, the sound would be distorted by obstruction and noise from other organs.
Just like a doctor with a stethoscope, plant owners must attach their vibration sensor (often known as an accelerometer) as close as possible to the centerline of the bearing. This prevents distorted signals from being received.
Double-Check that the Sensor is Firmly Attached
In order for the vibration sensor to correctly detect vibration behavior, it needs to undergo the same vibration movement as the vibrating component. Thus, the sensor should be firmly attached to the vibrating component to prevent any unexpected movement, rocking, or anything that would produce independent movements. This would mess up the measurements.
Many like to mount using a magnet, as it offers several advantages:
- measurement reliability
- convenience of use
To ensure it’s attached firmly, you need to stick it to an even magnetic mounting surface. An even surface will be free of dust, debris, rust, and flaking paint.
The magnetic mount must rest securely on the surface with the sensor positioned in the correct orientation.
In addition, the surface must be truly magnetic (iron, nickel, or cobalt alloys). For example, you cannot use aluminum with iron underneath it.
Do not drop or heat the magnetic mounting. This will cause it to lose magnetism. Also, be careful not to strip the screw thread on the vibration sensor or magnetic mounting.
Double-Check the Accelerometer is Oriented the Right Way
Depending on your needs, your accelerometer may need to be oriented differently.
For example, when detecting parallel misalignment, your sensor will need to be mounted in the radial direction of the bearings. When detecting angular misalignment, however, your sensor must be mounted in the axial direction.
The amount of vibration varies in different directions, so the signal produced by the sensor is dependent upon the sensor’s mounted orientation.
Mount the Same Sensor in the Same Location, on Something Substantial
To minimize inconsistencies in measurements, it is important to always mount the same sensor in the exact same location. Try to assign one specific sensor to one certain measurement.
Never mount the accelerometer on a flexible part of the machine. If you do this, the spectrum will be distorted by the flapping of that flexible piece.
In addition, make sure you don’t mount the accelerometer on lightweight machinery. The weight of the sensor and magnetic mounting can distort the vibration of the machinery.
As a rule of thumb, the combined weight of the magnetic mounting and accelerometer should not exceed 10% of the weight of the vibrating machinery.
Maintain the Accelerometer
Treat your vibration sensor with care. Throwing it around and being rough with it can lead to incorrect measurements and unreliable signals.
To mount the accelerometer to a magnetic surface safely, you must approach the surface with the magnetic mounting at an angle.
When removing the magnetic mounting, do not use the sensor as a lever for breaking contact. Instead, the mounting should be tightly gripped and tilted sideways in order to break contact.
Also, never twist the accelerometer cable, as it can lead to distortion.
Always take care to manage any possible hazards when measuring vibration. The most common hazards are:
- Injury by moving parts
- Magnet-induced damage
- Electrical shock
Don’t let the cable get tangled with the moving machinery. Do not rely on the quick-release connector to protect you from this, though it does minimize the likelihood. It should not act as a substitute for safe, correct installation.
Tie back long hair, and take care to avoid any loose or dangling clothing, data transfer cables, or straps.
To avoid electrical shock, do not attach the vibration sensor to any high voltage surface.
Finally, note that vibration sensors can cause damage to certain magnet-sensitive items, such as:
- pacemakers and other medical devices
- credit cards
- floppy disks
- cassette tapes
Which machines need vibration sensoring?
Unsure which machines should be monitored? The biggest thing to consider is that critical machines should be prioritized over other machinery.
Think of it like healthcare — it’s more important to heavily monitor the health of sick people than healthy people. The same is true with machines.
Monitor the following critical machines on a regular basis to avoid costly problems:
- Machines needing expensive/lengthy/difficult repairs if broken down
- Machines critical to production or general plant operations
- Machines known to frequently suffer damage
- Machines being evaluated for their reliability
- Machines which affect human or environmental safety
What is the unit of vibration measurement?
- Vibration frequency is measured in Hertz (Hz).
- The “f” symbol refers to the amount of times a vibrating object vibrates per second.
- The inverse of a vibration frequency is called the period (T). T=1/f.
Machine Vibration Severity is standardized by the International Standards Organization (ISO) within the ISO 10816 publication. Basically, it describes the acceptable vibration levels for four different classes of machines.
The chart below is an excellent reference point for analyzing vibration measurements.
For the ultimate in Vibration Sensoring, call Machine Saver!
Machine Saver is the most innovative vibration monitoring company in the manufacturing industry. Machine Saver manufactures and installs cutting-edge vibration monitoring solutions for reliable machine protection and condition monitoring. Want to learn more? Call us today at 832-471-8761!
Ultimate Guide to Vibration Sensoring | Machine Saver, Inc. – Houston, TX