Please communicate directly with Tim if you have some insight on his recent O&M problem

Good morning,

On Friday 11/27/15, our campus had a planned shutdown of power to the campus electrical loop. The shutdown lasted two hours and there were no problems with the restoration of power. However, on Monday it was discovered that four VFDs in our dining commons had failed. Initial reports were that this may have been connected to duct cleaning that was performed earlier in the week, but we then heard that they had been working after the cleaning and two days before the shutdown. An inspection of the drives by our staff showed no obvious signs of damage from moisture. The technician doing the inspection also found no other visible signs of failure (e.g. burnt circuit board). The building is 10 years old and three of the drives that failed were original to the building, the fourth was replaced 3-4 years ago. We have had outages over the years which have not resulted in this amount of equipment failure at one time. My experience says that this may be a matter of weak equipment or a surge when the loop was re-energized, but it is a bit odd. We have not found any such failures elsewhere on campus with speed drives or other sensitive systems. I was asked to see whether I could find any insight, so I turn to all of you. Please let me know if you have run across this or can give any other likely explanations.

Thanks very much,

Tim

Tim Garland, EFP

Electrical Shop Supervisor

Physical Plant

Keene State College

MS2502

603-358-2208

tgarland@keene.edu