Electricity + Control 2019

PLANT MAINTENANCE, TEST + MEASUREMENT round up

Vibration measurement in machine maintenance

ficiently as possible. Simple fixed and portable vibration monitoring instruments can assist in this. With good information or early warning on the condition of a machine, sound judgement can be used to decide whether or not to keep the ma- chine running and when downtime should be scheduled. With today’s technology, vibration measurement has become more cost effective and easier to install. User-friendly equipment allows simple 2-wire installa- tions that can provide system alarms and data to analysers for exact fault diagnosis. More sophisticated systems can be in- stalled on critical rotating plant to provide online, real-time analysis. These systems can also be linked to existing vibration sensors and, when made available on a lo- cal area network (LAN), can be viewed at any point on the plant or even around the country. By making vibration information available plant- or country-wide, such sys- tems enable the correct people to make the right decision, which can result in savings on downtime due to unnecessary maintenance or undetected failures. In the past, many processes would typ- ically be shut down on a routine basis for visual inspection of the machinery, wheth- er or not an inspection was required. Shut- downs, even scheduled shutdowns, have become increasingly expensive, particu- larly in today’s continuous processes. By

installing vibration monitoring equipment or using portable units on a routine basis the running time between shutdowns can be extended. R&C Instrumentation supplies and supports the RC range of vibration meas- urement products. These instruments are manufactured in Europe and conform to European standards in terms of manufac- ture, quality and reliability. In addition to the standard range of RC vibration sensors, ATEX certified intrinsically safe units are available, as well as a sensor with 4-20 mA vibration and 10 mV/°C temperature output. Portable instruments, raw data converters and programmable vibration switches also form part of the range of RC products. Enquiries: R&C Instrumentation.

Vibration and temperature are the most common parameters measured on pro- cess plants for machine maintenance. Temperature measurement has been in use longer, but vibration analysis provides an earlier warning and can offer more infor- mation to assist maintenance engineers. Most of us are familiar with vibration – a vibrating object moves to and from, back and forth. A vibrating object oscillates. We experience examples of vibration in our daily lives: a pendulum set in motion, a plucked guitar string, vehicles driven on rough terrain, all vibrate. There are var- ious ways we can tell that something is vibrating: by touch, feeling the vibration; by seeing the back-and-forth movement of a vibrating object; sometimes by hearing the sounds a vibration makes or sensing the heat it generates. Vibration analysis can be helpful in de- termining the exact nature of a machine problem and the spare parts needed for repairs can be ordered well in advance of the scheduled repair shutdown. The cost of equipment failure is significant, as is the cost of lost production due to a shutdown, particularly an unscheduled shutdown. Equipment that is not running efficiently also adds costs, in higher electricity usage and extra consumables, for example. It is important to keep a check on the mechanical health of a machine and main- tain it in operation for as long and as ef-

Tel: +27 (0)11 608 1551, email: info@randci.co.za, or visit: www.randci.co.za

Vibration monitoring instruments and analytics can assist maintenance engineers in deciding on scheduled shutdowns.

Electricity + Control

JUNE 2019

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