Click Here to Subscribe!

Click on the image and follow the Asset Reliability Road Map.

Reliality Roadmap

Follow us on

 

Building an Electrical Maintenance Program.

Mark Brunner. Mast.MM  Posted 16th April 2009.

Electrical control and distribution systems are generally complex and expensive assets that need to be effectively maintained so they operate at optimum performance over their serviceable life. It is common to find that there has been significant effort applied to managing mechanical assets, with less focus on electrical equipment. There are many reasons as to why this is the case, but the reality is that the way  asset management programs are developed should be applied equally to Electrical and Mechanical components of the asset. How many of you can associate with the following situations?

  • Down days and shutdowns are not  included as part of the production schedule.
  • There are few electrical tasks documented, and often the ones that are, often were a “kneejerk” reaction to a one off event.
  • Electrical maintenance spares are not kept in the store. Often they are kept locked in cupboards and draws of individuals.
  • There are many Mechanical Maintenance planners and few or no electrical Planners
  • There was no standard followed for Electrical drawings and hence most modifications occurred with hand drawn sketches at best.
  • Important technical information is not centrally located or managed.
  • There are few or no BOM’s for electrical equipment.
  • Run to failure was the primary strategy for all Electrical equipment.
  • There was no forward plan related to operational security of the equipment.
  • The CMMS system is not effectively utilised to record failure history.
  • Many of the Electricians are falling behind in their understanding of technology.

If you agreed with most of these comments then you will be working nearly 100% reactively and there was a lot of room for improvement, but where do you start? You can develop your own plan, tell people what they are now going to do and watch it all happen. Wrong! If you don’t manage the people side of the improvement, there is little hope of sustained improvement.

The People Issues.

1. Acknowledge your current situation.

You have to believe that there is a better way of doing things. If many of the above points apply to you then you need to know that your situation requires improvement.

2. Develop a vision for your Electrical Maintenance program.

The vision is where you want to be in the future. An example vision:

  • An Electrical Planner will be employed within the next 3 months.
  • All critical equipment will have maintenance strategies developed with 12 months.
  • Strategies for less critical equipment will be developed within 24 months
  • A system for the upgrade and management of electrical drawings will be developed and implemented in the next 12 months
  • All Strategies will maximize the use of condition based maintenance.
  • Tradesmen an other relevant personnel will be trained so they can effectively apply strategies.
  • Implement down days for Electrical equipment.
  • etc.

3. Get the support from the Electrical Workgroup. Discuss your plans for the future with your workgroup, after all they know the plant the best. Ask them for ideas to be included in the vision. It’s far better for the group to support the Vision and have a felling of ownership

4. Gain support from your management. If Management are not willing to support your vision then there is little chance of success. Document your vision, highlighting the benefits and prospective gains, and your ideas! Be prepared for some hard questions and be confident to back your judgment.

The Practical issues.

5. Resources will be required to effectively implement changes. As part of your vision presented to management it should have been made clear that resources are required to make significant improvements to your Electrical maintenance program. This doesn’t necessarily mean you need more people. Redeploying internal labor or hiring contractors on a part time basis usually make more sense. As your program starts taking effect, the efficiency gains will offset the loss of labor on the floor.

 6. Understand the criticality of your Electrical assets. You could use a criticality ranking tool for this, but if your assets have been around for some time, usually your employees will have a fairly clear understanding of this. The most critical assets will be your starting point.

7. Gather History of Failures. In established businesses, there are two areas to search for this data; from the CMMS or from experienced operators and tradesmen. What you are trying to do is understand what failures you have to mitigate by applying a maintenance strategy.

8. Understand other potential causes of failure. For new or very critical assets it is often worthwhile to perform a Failure Modes and Effects Analysis or Reliability Centered Maintenance process. These tools will determine “what could fail and what the effects would be” . This allows sound decisions to be made based on the Criticality of the effect.

9. Develop PM inspections and task lists that minimise known and hypothetical failure modes. Before generating any new PMs a review of current documents must be completed. You will find that some PM’s are adequate for the outcome required, but if they have not been reviewed for some they will have shortcomings. The example in the table below shows that for the 10 actions required only 4 were deemed to have PM’s that adequately address identified failure modes. 3 were average and required work, while PM’s did not exist for 3 critical actions. Your starting point in this instance is to develop the New PM’s for the 3 that are missing.


 

Actions required to address predominant failure modes on machine ABC.

PM for this.

Quality of inspection.

Freq

1

Servicing DC Motors

Yes

Good

8w

2

Gearbox oil tests

Yes

Good

6m

3

Maintenance of Sheaves, Rolls

Yes

Average

6m

4

On line testing of hot metal rolls. Thermography,VA

No

None

 

5

Servicing of Drains/cooling lines

No

None

 

6

Servicing of encoders

No

None

 

7

Cleaning of enclosures

Yes

Good

12m

8

Servicing of air conditioner

Yes

Good

6m

9

E/stop inspection

Yes

Average

1w

10

Cut-out inspection

Yes

Average

12m

Actions developed in New PM’s should be quantitative if possible, e.g, Measure brush length and replace if less than 40 mm long. Thermography is always the best option for detecting hot joints in control and distribution equipment where it can safely be applied.

For Electrical components remember the basics of CLEAN, COOL and DRY.

Thermography
Hot joints are the cause of significant downtime.

10. Ensure all strategy documents are captured in the CMMS and scheduled to occur during planned downtime. The development of strategies  including entering them into a CMMS is a very time consuming. Resources must be made available for this to be done in a timely manner. Not implementing strategy improvements in a timely manner will be viewed as negative by your customer. (Production. Management, etc).

11. Start on the BOMing process. For planned work to run smoothly materials must be listed against the equipment hierarchy so they can be easily identified and ordered. Critical equipment may need to be kept in stock dependent on lead time and the consequence of not having the spare. With electrical equipment there has always been the dilemma of equipment being made redundant within very short time frames, and this is often used as a reason to not start. BOMing should be part of an overall strategy review process. If new equipment is being installed demand a parts list from the Engineering Team running the install before the project is completed. Ideally the cataloging and BOMing of equipment should be part of the overall project.

12. Manage your  Electrical schematics and documentation. How often has a machine not been repaired in an adequate time frame because of the inaccuracies in Schematics? Do you have schematics hand drawn like the one below?

Accurate schematics are a critical part of your Electrical maintenance program. A schematic accuracy review should begin based on your plant criticality assessment. (The most critical assets first) The best place to start is to gather all paper copies of schematics for a single piece of equipment and have your most experienced electrical personnel check what is correct. From this develop one marked up copy of the schematic and have it stored electronically as either a CAD or picture file(jpg, tif, pgn, etc). You now have one updated schematic that can be accessed easily. For most businesses this will be a huge body of work initially, but the payoff is worth it and once your system is in order it is much easier to manage.  Ultimately the process of modification of schematics  needs to be proceduralised  and controlled.

13. Train your electrical personnel. Develop a training matrix for your electricians. The matrix should include an overview of specific and generic technologies and skills required of your people. An example of a specific skill would be; Access and monitor Allen Bradley PLC’s. A generic skill would be; Servicing of DC motors. You could also include the need for understanding of production processes, or just being familiar with a specific area of plant.

14. Ensure you have a documented process to effectively mange the workload. Most Electrical Maintenance departments whether they are one man or dozens have to prioritise their work. Prioritisation should not be based on “Who shouts the loudest” and should be based on Importance and Urgency. Importance equals the value to the business, where Urgency equals time limitations being applied to a task. Ricky Smith, Co-Author of “Lean Maintenance” and “Rules of Thumb for Maintenance Practices” says:
”The best companies have developed a proactive workflow model, that is understood and is followed by all levels in the organisation”The “workflow” model Ricky refers to needs to include a process for managing breakdowns, a process for planning a scheduling planned tasks, a process for managing work that will break a fixed schedule and a method for capturing improvements that can be fed into the system.

 

The Allied Reliability Workflow model.

15. Close the improvement loop. It is worthwhile reading about the Plan, Do, Check, Act Cycle; there are endless references to it on the net. All of the things discussed up to point 13 were related to Planning and Doing, whereas  the Check, Act part of the cycle is the key to closing the improvement loop. When any preventative maintenance program is developed it is not likely to be 100% up front. Aiming for 80% is a good start. The fine tuning will occur with feedback from the guys on the floor and  ensuring this feedback is captured and fed back into your system. There is nothing worse than a person highlighting where things can improved and then nothing occurs about it and no feedback is given. Remember, you can have great systems, but if no-one follows them you will not succeed in any improvement initiatives.

Plan Do Check Act cycle

It would be fair to say that it is much easier to write about this than implement it, but it has been done before and if you don’t start to do something you will not improve. Can any business afford this in todays economic climate?

For more info contact Mark at  markbrunner@thereliabilityroadmap.com

 

Please clink on the link below and rate this article. It will only take a couple of minutes.

Article survey

 

Anatomy of a significant lubrication failure. What can happen when critical strategies are not in place?

 Mark Brunner. Mast,MM   Posted  13-06-2009       

This failure described below is an excellent example of critical maintenance inspections not being in place, in-effective commissioning practices and the misinterpretation of warning signs before the major failure.

The event. A fitter was called to a large steel-processing machine that had suspected gearbox failure. On investigation it was found that all 8 gearboxes on this machine were in various states of failure.

Leading up to the event.

1. A few weeks before the lube pump was replaced as it was leaking. This pump is critical as all 8 gearboxes are lubricated by this system.

2. The pump was replaced, reconnected and tested. It was noticed at the time that the pressure gauge on the lube system was not installed, so it was assumed the pressure was OK as a pressure switch was fitted.

3. Not long after the lube pump was fitted the machine started to experience intermittent overloads and this event was captured in the CMMS.

4. These overloads were mistaken as problems with the braking system as brake problems were common on this machine. This is seen in a further three CMMS entries over a two day period.

5. These overloads continued to intermittently occur until one of the gearboxes failed completely.

6. On closer inspection all 8 gearboxes had major failures.

How did this happen?

James Reason introduced a now well known  concept called the “Swiss Cheese Model”(Fig 1).  Each layer of cheese represents a barrier that will prevent an unacceptable event from occurring, however each barrier has holes in it. When all the holes in the barriers line up then an unacceptable event may occur. The gearbox failures are a classic case of this model.

Fig 1. James Reasons Swiss cheese model.

 The following barriers were breached which lead to this incident.

Barrier 1. The oil lube pump had been changed because it was leaking. The replacement pump was not able to supply the correct pressure. This was not known.

Barrier 2. There were no standard instructions for the replacement of the oil pump. Therefore no test procedure.

Barrier 3. The required pressure was around 250kpa, but since the gauge was missing the fitter assumed the pressure was ok as the pressure switch allowed the machine to start.

Barrier 4. The pressure switch had been turned down to a dangerously low level at an undetermined time, for an undetermined reason. This allowed the machine to run with insufficient oil flowing to the gearboxes.

Barrier 5. There was no PM inspection in place to check the operation of the pressure switches

Barrier 6. The fitters and electricians misinterpreted the early warning signs of overloads as being problems with the brakes. 

The outcome.

The repair cost hundreds of thousands of dollars, and the machine was down for a number of months.  It was estimated that lost production was at least as much as the repair cost again.

After the event.

In this case the root cause was relatively easy to isolate which was the “Oil Pressure switch being set too low to protect the machine”. The incident highlighted a number of issues with the maintenance systems.

  • Why were uncontrolled changes being made to protection devices, and was this an accepted practice?
  • Why was such a critical device not tested periodically for correct operation?
  • Why was the required pressure setting not known by maintenance staff, or documented anywhere?
  • Why was equipment removed (pressure gauge) and why was there no plan to replace it?

These and other questions led to the following actions.

1. The causes of the failures were communicated to all tradesmen.

2. All other machines with similar systems were inspected to ensure the protection settings were correct.

3. The correct pressure was determined from the OEM., the pump repaired, gauge replaced and the switch set to the correct setting.

4. A manifold and three-way valve was installed for the purpose of testing the pressure switches either on or off line.

5. A PM instruction was developed and set for 6-monthly intervals to ensure all similar oil systems were checked for correct operation. 

The combination of the above actions has blocked a number of holes in the “Swiss Cheese model” effectively closing the loop which should ensure this  failure type, should not occur again.

Conclusion.

This failure was the most costly mechanical failure in the plants history. Planned maintenance inspections were in place for this machine but did not cover the inspection of a critical protection device. The maintenance Strategy had not been reviewed in many years and it is likely that a methodical strategy tool such as RCM would have recognized that this critical inspection should have been part of an overall strategy. If a suitable inspection were in the PM system it is highly unlikely this event would have occurred.

 Do you have any of these failures waiting to happen in your workplace? What are you doing to prevent these significant failures?

 

 

Further articles >>

 

[The Reliability Roadmap] [The Asset reliability Road] [The Eight Critical Elements of Asset Management] [Articles] [Articles pg 2] [The Logo] [Tools for Asset management] [About Us] [FAQ]

Copyright, Mark Brunner, 2009

The Country Road photo in the header is compliments of FreeFoto.com

website design software