Power analyser measures narrowband, full spectrum and harmonics simultaneously

June 18, 2014 // By Graham Prophet
According to instrumentation company ZES Zimmer Electronic Systems, in electric vehicle research and variable frequency drive applications, the fundamental and the full spectrum often have to be measured simultaneously, but users have had to choose between narrowband and full spectrum values. The LMG670 precision power analyser offers both at the same time.

The instrument's DualPath architecture enables the user to measure narrowband and full spectrum values up to 10 MHz simultaneously – free of aliasing defects – and to compare them in one view. The LMG670 can also measure harmonics and interharmonics up to the 2,000th order according to EN 61000-4-7; a single click is sufficient to toggle between RMS values and harmonics. An optional I/O card allows parallel measurement of speed and torque values in synchronisation with RMS power values.

The LMG670 can be equipped with up to seven power measurement channels and the user can choose between three types of power measurement channels, which offer different bandwidths and accuracies. The maximum obtainable accuracy is 0.015% of the measured value plus 0.01% of full scale. Common-mode rejection ratio (CMRR) of >120 dB even at 100 kHz guarantees accurate results when measuring applications with steep rising edges and high pulse frequencies. Optimal matching of current and voltage channels ensures precise results also at very small power factors.

All parameters, such as wiring, measurement range, filters etc. can conveniently be set via the 8.9-in. touch display (1024x600 WSVGA). Results can be displayed graphically as well as in tabular form, the user can easily switch between different views as needed.

ZES Zimmer Electronic Systems GmbH; www.zes.com