Electrical troubleshooting: 12-step program reduces downtime
Depending on the complexity of the problem, when performing troubleshooting activities the process may involve various levels of support and knowledge ranging from technicians, crew leaders, engineers and factory-trained experts.
Depending on the complexity of the problem, when performing troubleshooting activities the process may involve various levels of support and knowledge ranging from technicians, crew leaders, engineers and factory-trained experts. Taking steps to frame your thought processes in a methodical and logical manner can save you many hours of frustration, and possibly save the company thousands of dollars.
Typically, troubleshooting activities can be classified in two categories: simple and complex. Primarily, this article discusses simple troubleshooting techniques, but not so simple that you cannot apply this information to a complex issue. As a point of clarification, we are not discussing very basic or very simple activities. We are talking about those middle-of-the-road, tough to get right away, but not so tough that you can’t figure them out with a little bit of process discipline and analysis.
First things first
Regardless of whether it’s electrical, mechanical, hydraulic or pneumatic, the most important aspect of any troubleshooting endeavor is that the person performing the tasks is qualified and properly trained to interact with the equipment or systems involved. This is especially important with electrical equipment, as making the wrong decisions can end up costing you or someone around you serious injury or death
Before you begin any troubleshooting activity ask yourself: “Do I really know enough about this equipment or system, its operation and its construction to make sound, rational and safe decisions on the overall status?” If the answer is “no” or “I’m not sure,” get assistance and guidance from someone who has the proper expertise and knowledge to assist you.
The basic process
When you get a call to solve a problem or assess a symptom, unless you are the person who discovered the issue, you will need to be diligent in asking the right questions and preserving the conditions that lead to the issue at hand. Following a prescribed method to problem resolution is the key to getting satisfactory results in timely and efficient manner.
While each has varying degrees of complexity and/or applicable status, there are twelve basic procedural steps and topics to cover throughout the troubleshooting process.
Step 1: Initial problem identification: So what’s the problem? As the qualified person, identifying the problem is the key to capturing the issue at hand and getting a grasp of the situation. Using your knowledge and skills, you have to clearly identify the issue in your mind as a valid one, which then starts the whole process. If you determine at the onset that there really is no issue, but maybe operator error or lack of understanding, then after educating the person or persons that have the issue and training them on why it is not an issue, you are done.
For example, an operator states that the number 2 compressor will not run on third shift, and he thinks the motor is burned up. What he didn’t know is the compressor is on your energy management system and does not run at night. You educate him on the system operation and you are done.
But, if it truly is an issue then go to Step 2.
Step 2: Statement of the issue: It is important to provide a concise statement of the issue, especially to the person who initially presented the problem. For example, when the operator said the motor is burned up on the number 2 compressor, you listened to him and repeated items such as:
- Time and date the problem occurred (last night, third shift)
- What is wrong (the compressor motor is burned up)?
- What should be happening (the compressor should be running)?
- Why it is an issue (we don’t have adequate plant air)?
- Who else knows about the issue (can they corroborate the problem)
Step 3: Get the right people involved in the issue: Douglas Adams said “Human beings, who are almost unique in having the ability to learn from the experience of others, are also remarkable for their apparent disinclination to do so.” In addition to those who present the issue, it is important to bring in people that can assist in the overall solution to the problem. Besides yourself, and depending on how complex the issue is, you may have to bring in people from other departments; outside contractors or vendors; or specialists within your company who have “been there, done that.” Consider all your available resources from engineering, vendors, management, others in the industry or retired personnel still available for consultation.
Don’t be afraid to tap into the experience around you.
Step 4: Gather data on the issue: Before you begin your troubleshooting process, you must gather most, if not all, of the data surrounding the issue that exists at this point in the process. Without it, you can go down the wrong path and end up troubleshooting a portion of the system that is not even related to the problem. For example, if you follow the operator’s assumption that “the number 2 compressor motor is burned up,” you begin to lockout and troubleshoot the 4,160-V, 3,000 hp compressor assembly, going through the required steps and procedures to do so, without taking the time or steps to realize the controls were programmed to prevent the compressor from running during third shift. You have just wasted valuable time and prevented the operation of the equipment.
How much data you gather is directly proportional to the complexity of the problem and how much information you will require to make an informed and thorough troubleshooting process decision. But make sure you gather enough data to do your troubleshooting tasks properly.
Be careful when gathering data so that you do not destroy evidence related to the troubleshooting process. If need be, isolate the equipment and document the required information before the data is destroyed. For example, download or record trip-and-alarm data before resetting target indications. Also, you may need to gather items such as drawings and schematics, instruction books, vendor manuals, product recall bulletins, maintenance logs, trend chart logs, equipment history or design specifications.
Step 5: List possible failure modes: You know you have a problem (the number 2 compressor will not run), but what are the possible failure modes? Determine all of the possible failure modes and analyze each possibility for probable causes. Categorize each failure mode with a title. Under each title, list possible failure modes associated with that title. For example, “The number 2 compressor will not run.” Possible failure modes include:
- The motor is defective
- No power to the controller
- The control circuit is defective
- The motor is locked out for maintenance
- The protective relays are not functioning properly
- Process automation prevents start.
After listing the possible failure modes, determine which ones can be eliminated. For example, if you know that there is power to the controller, and you know that the motor is not locked out for maintenance, then you can eliminate those two failure modes. For the remaining failure modes, develop a plan to address each one systematically, and prioritized in the order of those most likely to be the cause of the failure.
Step 6: Develop a plan or procedure to execute: Often the troubleshooting of electrical equipment requires the device or system to be energized. This creates a multitude of issues that must be addressed. Issues such as personal safety, hazard risk analysis, energized work procedures, proper personal protective equipment required and potential impact to plant operations must be considered. You don’t want your troubleshooting procedure to cause additional equipment damage or interruption to facility operations.
To assist in the mitigation of additional problems or issues, a comprehensive plan, organized in a logical sequence, should be developed. Take in to consideration the most probable mode of failure, the likely cause of the failure, easiest actions to perform, which actions are non-intrusive and limit exposure to facility operations, if a similar piece of equipment can be used as a test device or simulator and finally, the availability of spare or replacement parts.
Step 7: Provide instructions to those around you regarding your plan: Your troubleshooting plan should be adequately communicated to those around you. If it is a simple process, then the communication is likely simple as well. However, even the simplest of tasks can have severe impact to operations. For example, while troubleshooting the No. 2 compressor control circuit, you de-energize the circuit, causing invalid alarms to the main control room. If the control room operators did not know the troubleshooting process was taking place, they may perform unnecessary actions to counteract the alarm status.
Your plan should include any possible unintended consequences of the troubleshooting process.
Step 8: Execute your troubleshooting plan or procedure: Now that you have an understanding of the problem, you have gathered the data and you have put together a plan that has been communicated to those affected; it is time to execute the plan. When troubleshooting electrical equipment, try to capture electrical parameters whenever possible so you have data that can be analyzed after the actual activities
This is the part of the process where you have to really be on your game, as any errors could have serious results or implications. As they say in scuba diving, “Plan your Dive. Dive your Plan.” Follow all of the necessary plan steps and precautions; use safe work and maintenance practices; document all the necessary results; record the test equipment used; and identify and record any changes that you may have made throughout the process.
Step 9: Analyze your results: Now that you have collected the data, you must make an informed judgment on the data and observations obtained. Compare these results to your expected results, and analyze the deviations. If something did not happen the way you thought it should or did not respond as you anticipated, correlate that data to the failure modes and see if there is validation to that particular failure mode.
Step 10: Identify the failure: While identifying the failure and replacing a defective component, be careful not to jump to conclusions on the failure mode as there may be other conditions that contribute to the actual failure. For example, the number 2 compressor motor has faulted, and you replace the motor. After installing the replacement, it fails after 24 hours of run time due to an overloaded condition and a defective protective relay.
The point is, simply replacing a defective component or piece may not be enough, especially when troubleshooting electrical equipment. Many components interact, and knowing how the devices interact with each other is vital in the overall troubleshooting process.
Step 11: Document findings: To help in the education and training of others (some of whom may be upper management), it is important to document as much of the troubleshooting process as is reasonable and effective. Photograph as much of the situation as possible. Digital pictures are cheap, so don’t be afraid to take several from all angles and perspectives. Write a comprehensive summary of the process and findings and place it in the equipment file or enter it into the computerized maintenance management system for future reference.
Step 12: Communicate findings through a lessons-learned session: If follow-up actions or activities are required, communicate and implement these as well. It may be that you have uncovered a situation that needs to be communicated to the vendor, to other shifts, to other plants or to industry through conferences and seminars. Documentation is the key to this process.
One of the most effective tools in communication is to have a “lessons-learned” session with the appropriate personnel. Explaining what you have found, and communicating those results to all parties involved is vital to help keep the issue from happening again or to reduce the likelihood or the number of incidents that a failure may occur.
There is no doubt that electrical equipment is prone to failure and problems. When those issues occur, electrical equipment troubleshooting can be a dangerous and daunting task. However, using qualified people who take the time to think through the problem, the troubleshooting process, the corrective procedures involved and who also document the findings, can help keep your facility running smoother with less downtime.
Remember: if you don’t understand the hazards, don’t attempt to do the task.
Ron Widup is the executive vice president and general manager of Shermco Industries