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There are times when permanent or continuous monitoring of a site is required. Examples of this are data centres, power critical manufacturing plants, and places where lives may be at risk through bad power. Ok, agreed, monitoring cannot predict a total power failure through a serious lightning strike, but it can help to see little things that are going wrong and getting worse - what is now being referred to as "predictive maintenance". Data centres are a prime example. There are unexplained crashes at a few servers. The same software is running throughout an installation, so it's not that. Without power quality recorders the engineers have no clue whether or not the power is to blame. Putting in temporary recorders after the effect is about as bad as shutting the stable door after the horse has bolted. But the situation goes further as there is also a requirement to see if transient protection is in fact halting the propagation of high speed events, and not becoming a node through the change in the lumped constants (in this case the capacitors found in the mains filters). Here, portable recorders are not a wise choice and one needs to consider fixed versions of the earlier mentioned portable 'full disclosure' power recorders. However, there is a new thinking that is required when it comes to fixed monitors. Actually, it is a very old thinking and one that used to be taught but is now almost absent in teaching in this modern society. It is called 'the basics'. When first wanting to become a radio 'ham' I never forgot reading "the radio amateur will have the ability to test transmitting frequencies to within 0.1% accuracy". This immediately makes one think 'digital frequency counter', when a well calibrated receiver would more than suffice - the latter being the advice from my Dad. In the same way, the design specification may call for "power quality monitoring" with a clear view to knowing there has been a power quality transgression. Yes, when wanting to diagnose what caused the issue then one needs really top-of-the-range recorders. But what if the recorder's only purpose is to alert someone to "please go and investigate any damage", or issuing an instruction to a software program to "go and test the status and reset if required"? Instruments that fall into this category >>
© 11.08.02 |
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