Bender RCMS490 Residual Current Evaluator Module

LINETRAXX RCMS490 residual current evaluator module is a multichannel residual current monitor designed to detect, evaluate and respond to fault, residual, and operating currents in earthed TN-S and TT power systems via external measuring current transformers. The RCMS490-D variant provides one alarm contact per channel, enabling local signaling or disconnection, while the RCMS490-L variant offers a seven-segment display for direct readout. For AC/DC sensitive (Type B) measurements, closed CTBS25 or CTUB100 series transformers are required and powered from a 24 V DC supply (e.g., STEP-PS); measurements can be configured per channel to be AC, pulsating DC, or AC/DC sensitive. The device analyzes harmonics, DC components, and THF with an adjustable frequency response for fire and plant protection, and data can be exchanged via a BMS bus; it is RoHS compliant. Typical applications include monitoring residual, fault and rated currents across installations up to 0–2000 Hz (CTUB100/CTBS25) or 42–2000 Hz (CTAC/WR/WS/WF), EMC monitoring in TN-S systems, and verification of PE/N conductor conditions to support safety and maintenance planning.