One such application is the quarrying and manufacture of aggregates for use in the construction industry. These materials include asphalt, cement, concrete blocks, roofing tiles, paving and kerbs and are used throughout the world in infrastructure, commercial, industrial and domestic construction as well as sports and leisure.
There are many quarries throughout the UK, and Trumeter has been able to solve a problem in the processing of raw materials for a number of these quarries. Processing the raw materials requires very powerful machinery to clean, crush and sort the various types of aggregates required. The machinery and conveyor belts are driven by electric motors and in a move to become more energy efficient, many quarries are replacing their old standard motors with variable speed drives (VSDs).
It is important that operators are able to monitor how hard the motors are working, to avoid damage to equipment and personnel and to reduce downtime. Traditionally a simple analogue meter could be installed with a current transformer onto a motor supply to measure current, and the operators could use the meter to keep an eye on things and make speed and process adjustments where necessary.
VSDs work differently as it is not possible to achieve an accurate current measurement in this way.
Trumeter is able to offer a solution in the form of the APM Process Meter. By configuring a VSD to output a linear signal proportional to its motor current, and scaling this within the APM it is possible show the true current reading on the display and bar graph. In addition, the APM dynamic backlighting can be configured to change the normal display from bright green, to a flashing red if a current reaches a critical level, alerting operators to problems as soon as they occur.