Simple-installation, 3-phase non-contact RMS current transducer

November 21, 2013 // By Graham Prophet
The RCTrms 3-ph current transducer from Power Electronic Measurements (PEM) delivers a convenient, safe and accurate solution for measuring current in three phases. It features a thin, clip-around, flexible sensor coil and provides accurate true RMS measurement with 4-20mA or 0-5V output, enabling simple installation with PLCs, SCADA systems or automation equipment.

DIN-rail or panel mountable, the RCTrms-3ph extends the design of PEM’s RCTrms single-phase transducer, connecting to three Rogowski coils to capture measurements from three current phases simultaneously.

With 18 current ratings options from 100A to 50,000A, and a choice of 300, 500, 700 mm or custom coil lengths, the RCTrms-3ph can be used in many applications and connected to a wide variety of SCADA systems, PLCs, data loggers, protection equipment or motor controllers. The clip-around coil design allows fast and easy positioning, and provides accurate results without needing to be centralised around the conductor. An isolated BNC-BNC cable-split option is available, to ease installation such as when threading through existing conduit.

RCTrms-3ph operates from a 12V-24V supply, and generates an accurate, true-RMS output as an industry-standard 4-20mA or 0-5V signal. The transducer provides a galvanically isolated measurement. Each unit is supplied with a traceable calibration certificate.

The RCTrms-3ph uses non-magnetic materials, which ensures excellent linearity and prevents damage from over currents. Typical accuracy is better than 1% of reading from 10 to 100% full scale. The units are safe, with 2kVdc power-supply isolation and 2kVpeak coil rating, and are CE marked and compliant with EMC EN 61326-1 2006 and IEC61010-1:2001.