New wide-band screened CWT Mini Rogowski current probes from Power Electronic Measurements Ltd. (PEM) featuring an innovative electrostatic screening strategy that enhances performance and accuracy in the presence of large electrostatic interference signals were introduced today at PCIM Europe. Combining a novel shielding technique, utilizing a low sensitivity coil and patented low-noise signal-conditioning circuitry, the wide-band screened CWT Mini probes boost immunity to local dV/dt transients while maintaining small size, flexibility, and 3dB bandwidth of up to 30MHz for a 100mm coil. The probes feature a coil only 4.5mm thick with 5kV insulation voltage, and can handle maximum current slope of 70kA/µs.
Engineers increasingly need the enhanced accuracy of a screened probe for measuring complex current waveforms in equipment such as UPS circuits, switched-mode power supplies and variable-speed drive (VSD) inverters where high power density leads to high field strengths, or where the high speeds and high blocking voltages of silicon-carbide (SiC) devices call for higher probe bandwidth and better common-mode immunity.
PEM's new wide-band screened CWT Mini probes eliminate the extra bulk and bandwidth restrictions imposed by conventional screening techniques, while delivering the known advantages of a Rogowski coil. These include zero insertion impedance, freedom from flying leads, isolated measurement, high peak-current rating, and the ability to measure small ac currents in the presence of large dc current.