Maintenance

How would you react if you found the security guard at your home, factory or office sleeping on duty? The natural course of corrective action it to reprimand him and ensure that he is not likely to behave irresponsibly in the future.

Circuit breaker, or for that matter all protective switchgear and other plant equipment which are being used in plant also can have irresponsibly and are analogous to guards sleeping on duty unless they are periodically “maintained”. For convenience Here I am focusing on circuit breaker maintenance only. During normal running of the plant the circuit breaker are seemingly cool and passive from the physical appearance which therefore, leads to a dangerous delusion that they are normal. And it takes an unfortunate accident or a serious fire to know that they are not normal. But than it is too late for any remedial action. This is not true only in this country. In the USA the study done by the committee setup IEEE found that “about half the circuit breaker purchased five year back were completely inoperative.” Such data, unfortunately would be very difficult to be formulated in our country. But the considering that training and tools are available here, one can imagine the magnitude of the problem.

It is only though a planned maintenance program that we can keep this guard on the alert. But let us pause and see what maintenance is all about. A common misunderstanding that needs to be cleared that MAINTENANCE IS NOT A REPAIR. It, repair is the result of neglected maintenance. And maintenance is the art of paying attention to piece a machinery before it has to be repaired. There will always be people to whom maintenance would seem a monstrous activity, People who find that the repair cost, considering the frequency of breakdowns, is lesser than the cost of maintenance.

Prima facie, the viewpoint does appear justifiable but if the overall economy is scientifically analyzed keeping in mind the indirect cost, the result could be shocking.

Comparison between planned maintenance & capital replacement

Planned Maintenance	Capital replacement
Cost X(Say)	Cost 3X(Say)
Avoid/Minimized breakdown	Carried out after shutdown
Can be done at continence	Done in emergency
Result guaranteed	Result may be short term
Quality and Scheduled unaffected	Quality and Scheduled can be affected
Spares can be ordered	Spares may be out of stock
Can take up during shutdown	Continuous service interrupted

Unfortunately, the above factors are invariably overlooked while brushing off maintenance as mere fighting of nuts and bolts. And many users prefer a repair job to a planned maintenance programme. It is time to reason: but Why? Perhaps because the breaker is only “carrying” current during normal conditions (A function that make them appear like ordinary cables) the maintenance personal may have delusions that the breaker is healthy. From our experience the most common Dangerous Delusions are:

1. All our transformer and breaker along with other switchgear have always run cool so that is the need of the costly maintenance programme?

A fault current ranges from 5600% to 2000% of full load current. When such a current is following, it does not really matter the cable were cool during normal loads or not.

The extent and frequency of the scheduled maintenance programme will depend on factors like:

Type of industry
Frequency of operation
Atmospheric condition

The gap between maintenance schedule can range anywhere between 6 months and 1 year. However, carry out detailed maintenance programme if any of the following events has come up.