Reliability maintenance requires periodic observation and data collection on assets that are deemed critical or vital. These assets should be monitored based on several things that should be considered when establishing the overall assets criticality. Some basic guidelines are as follows:
- Medium or High Voltage assets that require frequent starts.
- Medium or High Voltage assets that run continuously.
- Low Voltage assets that require frequent starts.
- Low Voltage assets that run continuously.
- Assets that have no redundancy
- Assets that are driven off Variable Frequency Drives, VFDs.
- Assets that have no spares or are of unique design.
- Assets that require a prolonged lead time to acquire parts.
- Assets critical to safety or environmental issues.
Of course, there are other considerations, however these provide you with same guidance for initial prioritization. Some other things to consider is application. You may have a medium voltage 10,000 horsepower motor, obviously critical. What about the fractional horsepower motor that provides lubrication to the bearings on that 10,000 HP motor? That motor is every bit as critical! Determining criticality is a task that should involve a concerted effort of various functionaries at your facility. Maintenance, Production, Planning, and Safety personnel should all sit down and mutually discuss asset criticality. Once equipment is listed as critical, then the periodicity of monitoring should be determined.
Gather all the equipment drive train and motor nameplate information. A recommended practice is to list all your assets in a spreadsheet using software like Excel. Once you have a list, segregate the equipage by location. For example, all motors in this building or that building. Then group by MCC or starter number. Every piece of equipment should have a unique identifier. Common equipment can share similar alpha numeric labeling, but- must have something unique to that asset. Let’s take a Boiler Feed Pump for example, you have 4 of them, they can easily be labeled BFP-1, BFP-2, BFP-3, and BFP-4. That would give a system designator. Each component of each system needs a label or asset ID that associates with the main system. BFP-1 Starter, BFP-1 Pump and BFP-1 Motor. Let’s go one more step, we need a total unique identifier for the motor. We have 4 boiler feed pumps, their respective motors and 2 spare motors. Anyone of these motors can be in any one of the locations over the years and possibly they are compatible with other equipment’s as well. When we test critical motor assets, we need to track them individually. That way we can determine if a motor is not displaying normal longevity between failures. We recommend a 4-to-5-digit serial number be assigned to each motor, that is unique to that motor. Letters can lead to confusion, it that a zero or a letter O, is that a 1 or a l an 8 or a B etc. Now we can track a motor from the warehouse to the scrapheap, regardless of where it has been installed, under whatever equipment number.
When building a database, you should group all assets in the same location together, you can further group them when they are availed from the same MCC or starter group. This will make testing much more expedient.
The “Plant Layout,” or database “hierarchy” should follow a format similar to this:
Building or Plant Location
- MCC or starter group
- MCC Bucket or Starter ID
- Asset ID
- Asset ID for the motor location
- Motor Serial Number
If you want to limit the number of levels in the “hierarchy,” you can remove the MCC levels as shown below:
Building or Plant Location
- Asset ID
- Asset ID for the motor location
- Motor Serial Number
It is extremely important, regardless of the hierarchy levels, that the last level is a unique identifier for the motor.
For more information on motor asset management or motor testing and evaluation, consider attending one of Snell Groups motor training classes. In addition to our formal live courses, we will soon be offering “On-Line” courses as well as virtual presentations. For more information visit our website, www.thesnellgroup.com.
While there, take a look at our Electric Motor Testing Data Analysis Wall Charts. We offer one for de-energized testing and one for power quality and energized testing.