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Case studies

Moeller helps Mono to control the munchers!
Easy relays make blasting safer for Tarmac
Moeller 'Rasuls Up' a solution
Relay keeps an eye on the dough
The Ecotech Centre in Swaffham turns to Moeller's easy control relay
Taking the lead in lead monitoring
Mass finishing technology: Control and operation with MFD-Titan and easy800
Precision sharpening with MFD-Titan

  Easy relays make blasting safer for Tarmac

By eliminating the need for costly cables, easy800 intelligent control relays from Moeller Electric are providing Tarmac Western, a leading UK supplier of aggregates for the construction industry, with a convenient, dependable and cost-effective solution for remotely controlling a Klaxon sounder used to give advance warning of blasting operations in the company's Shrewsbury quarry.

To ensure safety in the quarry, it is essential that a loud audible warning be given close to the location where the blasting is to take place. This location is typically 200 metres or more from the site control room. The traditional solution would have been to run an ordinary control cable from the control room to the sounder.

Low voltage control would, however, have been problematic because of the voltage drop in the long cable. The alternative of using a higher control voltage was also unattractive as, in order to meet quarry safety requirements, it would then have been necessary to use an expensive armoured cable for the link.

Working with Moeller Electric's customer support team, engineers from Tarmac Western solved the problem with two Moeller Electric easy800 intelligent control relays, one in the site control room, the other close to the blasting site.

Primarily designed as a versatile, inexpensive and easy-to-use alternative to conventional electromechanical devices, the easy800 units feature a built-in easyNET communication interface.

In the Tarmac application, this communication facility was used to establish a link between the two relays using readily available low-cost network cable. The relays were then programmed so that key switches connected to the inputs of the easy800 in the control room operate devices, including the Klaxon sounder, which are connected to the other easy800 near the blasting location.

Since the network connecting cable between the easy800 relays carries only small signal currents, voltage drop is not an issue. Also, because it operates at low voltage, it is not necessary for the cable to be armoured.

“The cost of the two easy800 relays and the network cable was much less than the cost of installing conventional cabling,” said Paul Bishop, electrical engineer at Tarmac Western's Shrewsbury site, “and using network cable made the installation work easier and less time consuming. Setting up the system was straightforward and, on the few occasions we did need advice, the support we received from Moeller was excellent.”

The easy800 installation at Tarmac Western's Shrewsbury quarry has now been in use for several months, and has performed faultlessly. “It may be a slightly unusual application for these products,” said Paul, “but it certainly saved us time and money, and it's working well!”

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