Howard W Penrose, Ph.D.
VP Electrical Reliability Programs
T-Solutions, Inc.
hpenrose@tsoln-inc.com
“Maintenance consists of actions taken to ensure that components, equipment, and systems provide their intended functions when required.” – NAVSEA MIL-P
“We do maintenance because we believe that hardware reliability degrades with age, but we can do something to restore or maintain the original reliability that pays for itself.” – NAVSEA MIL-P
“Failure is not an option!” – NASA
“Failures Happen!” – NAVSEA MIL-P
The Concept of RCM-Based Motor Management – Part 1
In order to understand the next few days of RCM-based concepts, we will set a few definitions within today’s lecture.
It is important to understand that good maintenance preserves the function of the equipment. The definition of function that we will use will be: “Any action or operation which an item is intended to perform.” - NAVSEA MIL-P
Within the function, there are a number of classifications:
• Active: Requires activity of an item
• Passive: Requires an item to be inactive
• Evident: Its loss if obvious to the operator
• Hidden: Provided by an item for which there is no immediate indication of malfunction or failure; Demand for such functions usually follows another failure or unexpected event.
• Online: Continuously or continually provided during normal operations. When we discuss CBM equipment, this will refer to instruments used to evaluate condition while equipment is energized.
• Offline: Not continuously or continually provided; Activated by some action or event. When we discuss CBM equipment, this will refer to instruments used to evaluate condition while equipment is de-energized.
Here, we also want to make another point: The intended function of a piece of equipment may be something other than the full design capability, either more or less. It may be that loss of a particular capability of a machine may not impact the intended function of the equipment. In this case, it would not make sense to evaluate or correct the condition of the unused function. As such:
Not All Failures Need To Be Prevented!
This is one of the key principles of effective maintenance. This is also one of the purposes of Reliability-Centered Maintenance (RCM).
RCM utilizes the principle of risk management to evaluate what, if any, maintenance should be performed on equipment. Risk = Pf x Sf; where Pf is Probability of Failure and Sf is the Severity of Failure. Understanding the risk allows us to put our resources where they provide the greatest benefit.