Power Electronic Measurements (PEM) has launched its latest generation of Rogowski coils for non-contact current measurement, designed specifically for monitoring today's most advanced power systems and semiconductors. The new CWT Ultra-mini probe offers higher maximum frequency and increased stability over a wider operating temperature range. The CWT Ultra-mini current transducer is a powerful development or diagnostic instrument for examining switching waveforms, ripple currents, transients or harmonics. The extended temperature range of -40°C to +125°C and improved temperature coefficient of 50ppm/°C allow accurate measurement of semiconductors operating at increased temperatures. In addition, the wider 3dB bandwidth of 30MHz enables engineers to analyse high-order harmonics in systems operating at high switching frequencies, or accurately monitor switching waveforms with rapid rise-times. The coil has a cross section of 1.6mm, allowing users to take measurements at locations that are difficult to access. It can be positioned between the pins of MOSFETs or IGBTs in packages such as TO-220 or TO-247. The complete CWT Ultra-mini range comprises several variants suitable for measurements from as low as 1A to a maximum full-scale current of 6000A. The new family also has enhanced transient response, and can measure fast-changing currents up to 80kA/μs and has typical measurement accuracy: ±2%. PEM has special expertise in wide-band Rogowski current probes, which allow alternating current to be measured accurately by integrating voltages induced in the coil when looped around a current-carrying conductor. Since no electrical contact is required, this provides a convenient means of measuring current without effecting circuit performance. PEM's clip-around coil design allows fast and easy positioning, and provides accurate results without needing to be centralised around the conductor. Power Electronic Measurements
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