Feature Machine Safety


or most manufacturing businesses the only critical issue when it comes to power is ensuring the lights stay on. This is entirely reason- able as any interruption in the supply can result in unwanted downtime - lost orders and wasted man hours. However, by focusing solely on power continuity these companies are missing a serious trick and in doing so risking potential damage to their equipment and their bottom line. In most instances, the quality of the power rather than its continuity is a much more serious issue in factory environments - but it is a problem which largely goes unnoticed with few people even aware of it. But what is it and what effect does it have on factory equipment? Poor quality power can be defined as any serious irregularity in the voltage magnitude of the power supply and include power surges, spikes, impulses, electrical noise or ‘pollution’ in the electrical circuitry.


Irregularities in supply


These irregularities in the power supply have many different causes. Often the power sent down the line can be seriously polluted – outages or brownouts in the grid can cause sudden large spikes or surges in the power. In addition, problems can orig- inate internally as a result of the actions of end users themselves. In a factory setting large loads including motors, relays and drives can introduce power quality problems


Danger behind poor quality power F


In most instances, the quality of power is a more serious issue in factory environments than its continuity but it is a problem which largely goes unnoticed, writes Rob Morris, country manager at Powervar UK


into the system. For example, a large motor being turned on and off can cause sudden and unexpected increases in voltage inside the electri- cal system. These incidents of poor quality power can often have disas- trous effects on factory equipment and machinery. Damage can often be cumulative and unseen where con- stant but low level noise or pollution can degrade equipment over time. On the other hand, spikes in voltage can completely knock out equipment in one fell-swoop. This is particularly the case with much of today’s sensitive electrical equipment and complex micro-circuitry.


Equipment including PLCs, comput- ers, CNC systems and robotics are par- ticularly susceptible to poor quality power. If they are connected to the same electrical circuits as larger pieces of equipment such as motors or relays which themselves can pollute the cir- cuit, the effect can be amplified. Damage to equipment can translate to downtime, unfilled orders and wasted man hours. For example, for a manufacturing plant that produces integrated circuits, a serious power quality incident might shut down the entire operation. In many cases it could take 30 hours or more to recali- brate tools and instrumentation and bring it back to full production. Similarly if a digital printing press is disrupted, the ‘make-ready’ process which is used to run the job must be repeated with make-ready being the


Powerful safety light in low cost multi voltage beacon


eflecting in every sense their place at the cutting edge Curtis Instruments has introduced a low cost multi voltage beacon that offers customers an inexpensive and powerful safety light that unlike conventional xenon technology requires little or no upkeep during its long lifetime. LEDs have a solid state construction which strongly resists shock and vibration (great for industrial or construction trucks); they are incredibly bright which means they can be used indoors and outdoors; they last longer and use less energy. The new Curtis LED beacon features a constant ‘on’ option, links to speed controllers to provide fault warning flashes if required; and is backed by a 2-year warranty. Notable dimensions are 120mm high by 148mm wide.


R


Curtis Instruments T: 01604 629755 www.curtisinst.co.uk


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most expensive non-material cost factor in this process. Incidents of poor quality also mean frustrating call outs to service engineers who are forced to look for faults or errors with machin- ery and equipment which don’t exist - again pushing up costs.


Power outages


Many businesses are alive to the threat of power outages and blackouts and use uninterruptible power supplies (UPS) in order to mitigate the effect of these incidents. Yet power outage is relatively rare - lasting on average for about seven hours per year in most developed countries, whereas a typi- cal factory of office facility can experi- ence thousands of power quality incidents every year. Most UPS are not equipped to deal with these problems. To meet the challenges presented by poor quality power, UPS must be equipped with power conditioning components which help to maintain a clean and continuous source of power to critical equipment. To ensure full protection, only UPS which include an isolation transformer, surge diverter and noise filter will eliminate the problems of voltage spikes and surges and electrical noise.


Power conditioning


In simple terms, this power condition- ing equipment takes poor quality power and ‘cleans’ it, eliminating the irregular power and sending a reliable and uncontaminated flow of power to critical systems. As a result equipment and machinery is able to function as it should without interruption or disrup- tion. By eliminating these issues through the use of power conditioning equipment, manufacturing businesses can prevent downtime and wasted labour and expensive raw materials which happen as a result of damage to critical equipment and systems by poor quality power.


While many businesses believe that UPS alone are enough to protect them- selves and their equipment, only supplies which are equipped with power conditioning equipment com- ponents represent complete and total protection from problems associated with poor quality power.


Powervar T: 01793 553980 www.powervar.com


NOVEMBER/DECEMBER 2013 Factory Equipment


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