| | 
Traditional condition monitoring still makes use of many different typesof parameters such as temperature, pressure, torque, position and others, but measuring these directly can be inefficient and inaccurate. Measuring the input current of a load provides much more information than just the current value and has a number of advantages:
Speed– load changes are detected immediately, which can prevent equipmentfailure and process disruption.
Ease of use – a contactless currenttransducer or switch can simply be snapped over a cable, without theneed to screw or weld on complex brackets. Furthermore it can be installed in electrical control panels – thus avoiding complex wiring – toremotely monitor devices that often operate in harsh environments. Inparticular, since they are so easy to fit and put into operation, theself-powered split core current transducers can be retro-fitted into existing installations without shutting down operation.
Reliability– solid-state transducers are more robust than electromechanical devices and require no maintenance.
There is an increasing number ofcondition monitoring technology applications requiring accurate measurement and precise control of electrical parameters. But in some casescritical status feedback comes too late, or not at all, and can evenresult in harmful and expensive damage.
Advanced information about the technical process can be provided at an early stage by installing electronic current and voltage transducers with integrated signalconditioning. While making the necessary measurements of the electrical parameters, these integrated transducers also provide the additionalinformation required to ensure that reaction comes quickly and reliably. They are at the heart of many state of the art industrial supervision and automation solutions.
Characteristics
Unlike traditional measurement using basic current transformers, LEM integrated transducers combine the most advanced AC & DC sensing technologies (e.g. Hall effect or PRiME™) with signal conditioning electronic circuits (True RMS, active power calculation, threshold detection, etc). Thanks tothe True RMS technique they can accurately measure current propagation, even on non-linear loads or in noisy environments. They output an electrically isolated 0-5VDC, 0-10VDC or 4-20mA standard signal that can be directly handled by any PLC or monitoring device.
These products require complex adjustment and calibration operations and benefit from the LEM technology and manufacturing know-how to achieve the highest performance and quality level of the market.
Application examples
Installing automation transducers in control panels or on electric motor drives allows monitoring the status of various kindsof electro-mechanical installations, alarm of a failure or to automatically start a backup system. LEM integrated transducers are suitable for monitoring DC and sinusoidal or distorted AC signals in the most diverse of application areas:
Safety operations and personnel protection - e.g. safety lights monitoring, ground fault detection
Process control and product quality - e.g. monitoring current of industrial electrical heaters, electrolysis process in the chemical industry
Maintenance operations – e.g. pump jam and suction loss protection,dull tool indication
Facilities/infrastructures – e.g. monitoring DC power supply and Battery, HVAC systems, cathodic protection of metalstructures, etc.
Energy production and consumption – e.g. monitorwind power plants or solar panels, site energy sub-metering
Concluding remarks and prospects
Monitoring the current drawn by manydifferent types of electrical loads allows a wide range of problems to be detected – often before they cause a system failure or have a noticeable effect on product quality. With today’s economical PLC systemsand the ever-increasing choice of integrated transducers this efficient monitoring and diagnosis technology is now possible for the most diverse kinds of applications. In a trend to distribute the informationprocessing close to the measurement devices, the integrated transducers become more and more “intelligent”, enabling a fast response to abnormal conditions, enhanced reliability and reduced installation complexity and cost.
| |
