When I was six years old – admittedly some time ago now – we visited a real, working windmill. One of the bigger ones that feature on pictures advertising Holland, usually in combination with cogs and Delft Blue chinaware.
The windmill was operating, grinding flour. The noise, and the dust, and the vibrations left an everlasting impression on me. I remember vividly the steep, precarious stairs (without rails) between the multiple floors. On the narrow top floor was the drive and bevel gear section. On the floor below was the mill proper, grinding the flour. Then there were two or three more floors below, on each one things were happening and moving – I have no idea what. Trap doors opened and shut and full bags of flour dropped with loud bangs and amidst clouds of dust from floor to floor. All moving things were connected with one rope, and this rope was connected to the one drive: the windmill.
One drive. That has been the key issue for human beings for hundreds, possibly thousands of years. We had wind, we had water, and we did not have pretty much more to drive things about. The last couple of hundred years we invented steam. But a steam machine is a complex and expensive device, and once you have one, you want to use it to a maximum extent.
The “one drive” principle has been the paradigm for engineers up until very recently: in cars, we used the motor to drive pretty much anything else. In our industry, we tried – and to a certain extent still try – to use as little as drives as possible and to loop them through and link them. An example is the line shaft conveyor: one big drive, with a long shaft around which little belts turn the rollers. We could make curves and go as far as 30 meters with one drive. I am saying “could” because we have taken this type of conveyor out of our range.
Pneumatics are similarly an example of the “one drive” principle. I will write later about the future of this technology. For now suffice to say that it is an application with one “central” energy source applied time and again throughout a factory.
The world has entered a new engineering paradigm: distributed drives. We no longer try to use as few drives as possible – in fact we put drives all over the place. This is easy to observe in cars, where windows have since long been actuated by a small electric drive. More recently, electric steering assistance has been introduced. In our business, we see motor rollers. We see pneumatics being replaced by electric motors or actuators.
Why is this? You see, we come from a past where things were expensive, or rare, or non existent, and people were cheap. This has been going on for over thousands of years. There was ONE windmill in a given area, building a second one was difficult and expensive and probably forbidden anyhow. Up until the seventies, salary costs did not loom too large in the budgets of companies, whereas electric drives cost a small fortune (with some exaggeration to make this article a little more juicy). So engineers HAD to reuse this power source where they could. The fact that this one drive caused engineering time and complex installation time was a secondary consideration.
Nowadays, people are expensive and hard to get. Things are cheap. Engineers have to focus on reducing engineering time together with assembly and installation time. This forces us in the direction of “distributed drives”.
There is, however, a much more important advantage to the distributed drive paradigm, which is modularisation. Modularisation makes standardisation possible even for small series such as are common in our industry. Standardisation is, of course, key for survival as it is the one thing that helps us ensuring things are safe and as cheap as possible. In addition, distributed power makes distributed intelligence possible, which is the next paradigm shift we see in our industry. But that is for a later article.
Maarten van Leeuwen
Group Managing Director
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