A couple of years ago, your plant engineer had the foresight to install a power monitor on the feeder supplying your plant air compressor motors. Shortly after its installation, the power monitor revealed some power anomalies. Those were resolved.
Recently, the plant engineer ran an energy usage report going back a year. About six months ago, the compressor motors began using much more electricity at an additional cost of nearly $4,000 per year. There aren’t any power anomalies, motor problems, or VFD problems to explain this.
A contractor performed ultrasonic leak testing; the firm found and repaired a few dozen small leaks. But these leaks don’t account for the excess usage or the suddenness with which it appeared. Where should you look?
Because of the suddenness of the energy usage jump, the likely culprit is a system maintenance or design change. Compressed air must have liquid contaminants (e.g., water and lubricants) filtered out, and these filters must be periodically drained to keep working. Excess air loss here would cause the compressor motors to work hard, thus explaining the spike in energy usage.
Are the filter pots drained manually on a PM schedule and/or by operators? Perhaps too rigorously now? Or perhaps there was a problem in manually draining the filter pots enough, so timer drains were installed and they are set to drain too long and/or too frequently. Run these ideas past the plant engineer.
