Recently I was stuck in traffic on the motorway and, being a Motion Control engineer, I was musing on the theory of conservation of energy as one does. This led me to thinking about the ways in which this theory also guides us in devising the most cost efficient ways of satisfying our clients need for performance in their production systems.

This was probably prompted by a recent project I was asked to work on in Kiev, Ukraine. The task was to upgrade the performance of a bag making line. The output requirement was specified by the client so we knew what speed was involved. This indicated a motor speed of 1000 rpm at approximately 20 Amps.

This in turn indicated the selection of a 4000rpm motor, the closest fit at this rating, and its associated drive totalling a list price of £2600. However, knowing that we had speed to spare, we then looked at adding a 4:1 ratio gearbox to the spec which then, as a result of the reflected inertia calculation, allowed us to come down two sizes of motor and drive achieving a total list price of £2000 while still delivering the performance the task requires with the minimum of wasted cash.

The savings don’t stop there as this specification reduced the cost of cabling and switching required as well. A further benefit of this type of specification is that as we are able to use the full range of the motor it gives as a much finer degree of control to fine tune performance

The same approach directly increased the profit margin for a Black Country maker of Feed Presses. I was asked to look at the spec for these machines and my calculations indicated that they were using a motor that appeared to be much larger than the standard usage required. When questioned the answer was that that was the way they had always done it. I persuaded them that they could achieve the desired result with a good quality motor one third the size and £1000 less expensive. As a result they could then be both more competitive and profitable on every sale.

It is important to recognise that neither of these examples are a case of using cheaper components but the right size quality components for the job that cost less.  These are solutions that not only optimise the use of energy but cash as well.

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