The range of RCTi ac current transducer equipment produced by Power Electronic Measurements Ltd has now been extended to include a 3ph version. In common with their other recently introduced single phase products, the RCTi-3ph is an industrially specified unit, designed for permanent installation, and suitable for use with oscilloscopes, data acquisition cards, power analysers and in power quality applications.
The flexible, clip around coil sensors are based upon Rogowski technology and can be easily retro-fitted. Each coil is thin and lightweight, with three standard lengths which can be specified independent of measured current (from 500A to 50kA). All coils are connected to a small single enclosure electronic integrator, which can be DIN rail as well as panel mounted. A single isolated power supply (12 or 24V as standard, others including 48 and 110Vd/c also available) minimises cabling, helping to ensure a low cost per channel. The unit can also be specified with BNC plug, detachable coil-cables for easy cabinet and control panel installation.
Other features shared by both the 3ph and single ph units are non-intrusive operation, with no power drawn by the coils from a circuit under test. There is a predictable low phase shift with power frequencies of 50/60Hz and above, with wide-band width 0.6Hz to 800KHz for measurement of sub and higher frequency harmonics and complex waveforms. The RCTi-3ph is an ideal replacement for medium/large current CT’s (current transformer), but unlike a CT it is intrinsically safe to use because there is no danger of open circuit secondaries, high current surges or magnetic saturation.
A reading accuracy of ±1.0% is claimed with an output load of greater than 10kohm, within an operating temperature range of -5ºC to +65°C. The product is CE marked and complies with EN61010-2001, EMC EN61326. The product can also be customised for coil/cable lengths, current/output ratings, frequency responses and phase error requirements at different frequencies.