Do PM Benifits Outweigh Harm???

[Don S.]

To PM or Not to PM is the wrong question. What to PM and at what frequency is the right question. Every facility has unique factors influencing the health of its equipment, and unique consequences of equipment failure. Due to manpower and budget issues, our 40 substation, facility?s robust PM program became seriously degraded, duration of activities being extended 3&4 times their former schedule. Fortunately no serious damage or outages occurred but when we got back in to it we learned quite a bit. For example the dry type 13800 primary transformers we had been servicing annually got along just fine for 3-4 yrs. The 480V draw out breakers that rarely had any issues on their former 3 yr schedule were a different story. Several would not trip or could not close after being opened. One was jammed up in the gear due to deterioration of mechanical parts, some had problems with the electronic trip units. PMing is a ?pay me now or pay me later? fact of life.

 

[zog]

The 480V draw out breakers that rarely had any issues on their former 3 yr schedule were a different story. Several would not trip or could not close after being opened. One was jammed up in the gear due to deterioration of mechanical parts, some had problems with the electronic trip units. PMing is a ?pay me now or pay me later? fact of life.

The problem there is that in the field breakers can not be properly lubricated per the manufactures instructions, testing guys just use spray lube, or "tech in a can" which evaporates ina short period of time and actually removes the correct greases from the operating mechnasim. You are better off refurbishing your breakers every 10 years than doing a quick clean and test every 3 years. EPRI has done a lot of research on the 2 types of PM's.

 

[Don S.]

You are correct. There are ?check in the box? PMs, and there are serious PMs done by knowledgeable employees who know they?ll be the ones dealing with the equipment long term, and that they?ll be accountable when things don?t work. The majority of our breakers are 50 yrs old, have been retrofitted with electronic trip units, and will easily last another 50 yrs. They get a current injection test, inspection, and proper lube on moving parts. The newer breakers will never make their first 50 yrs. Spray lube is for the ?check in the box? guys.