Motor-Driven System Improvement Projects

2 replies [Last post]
meby's picture
Joined: 2012-04-17

The Motor Decisions Matter campaign is no longer just focused on motors. In mid 2013, the program expanded to include motor-driven systems. Do you have any success stories you can share with us, which delivered substantial energy cost savings?

USS Hornet's picture
Joined: 2015-01-07

This example is a simple one but one that did save on energy waste. We installed an L.P. air compressor and tied it into the ships expansive distribution system. It supplied air for pneumatic tools primarily used by the aircraft restoration crew. They work three days a week in the mornings. They and others always forgot to turn it off when done. I would arrive in the morning and it would be on and cycling, infrequently, but still cycling. I got tired of trying to educate people to turn it off so I devised a timing circuit to shut the system off at a preset time.

The timing circuit consisted of a control transformer (460-120VAC), a control relay, two push buttons-one on and one off, a solid state interval timer, an indicating light, a fuse holder and a timer by-pass key switch. I set the timer for four hours. Depressing the start button would turn the "system" on permitting the compressor to cycle via the presser switch. After four hours the "system" would shut off and reset itself. Depressing the start button would activate the operation again. Depressing the stop button would stop the operation and the controller would reset.

The air compressor now runs only when needed.

USS Hornet's picture
Joined: 2015-01-07

Another example I just thought about involves the operation of our boat and airplane crane. The crane consists of two independent hydraulic systems featuring a rotate system and a raise/lower system. There are two 50 HP motors driving the pumps, one for each system.

Normal operating practice was to turn both pumps on at the beginning and let them run until the lifting evolution was complete. This meant that the motors ran unloaded (pumps at 0 stroke) about 80% of the time. The actual lifting time was only 20%.

I instructed the operators to turn off the motors during idle periods to conserve energy. A motor running just one minute after starting consumes far more energy that the energy to start it. Doing this saves on kWhrs as well as demand charges.

I monitored the motors for heat increase due to the frequency of starting. The motors actually ran cooler than before. I checked the starters' main line contacts for increased wear, none were noted. Also, no mechanical stresses were noted.

The crane has been operating this way for about five years.

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