Early Fault Detection in Electrical Installations
Any damage may cause breakdown of process, so the continuous monitoring of safety relevant circuits for fault, residual and operating currents as well as for stray connections is necessary. Residual Current Monitors (RCM) from Phoenix Contact allows one to avoid unexpected shutdowns due to residual currents. RCM units continuously monitor the current leakage and are able to detect insulation breakdown in cables and equipment at an early stage. The units are a combination of monitoring and early fault detection in one. They provide electrical operators all the benefits of having this information in advance. With this information, troubleshooting and repairs can be performed early on before they cause a breakdown on the site.
Differential current monitoring
RCM works on the principle of differential current monitoring. The devices are available for AC and DC circuits. Differential current monitors feature a wide range AC voltage input for voltages of 85 V AC to 264 V AC (50/60 Hz). An LED strip shows the current residual current as a percentage of the preset full value. In addition, one can also set limits for a pre-alarm and main alarm. These settings are adjusted to the specific requirement of the end user. Two separate floating changeover contacts are provided on the monitor to report to an external system if the pre-alarm or main alarm has been triggered. The differential transformers inductively record the differential current on live conductors going to the system being monitored. For this reason, all live conductors for the power supply unit pass through the transformer. Insulation faults, when they occur, may cause a difference in current in the live conductors. This is detected by the differential transformers and analysed by the differential current monitor. By using Phoenix Contact RCM device, fault currents can be detected and signalled early, before they reach critical values. The result is less downtime, while at the same time the availability and productivity of the production systems are boosted. The Current transformers are available in diameters starting from 20mm to 210mm.