The moving-iron meters ER 72/96/144 with profile scale are mainly used for measuring AC currents and AC voltages in the usual technical frequency range of 16 2/3 ... 100 Hz (ER 72/96) or 15 ... 65 Hz (ER 144), with special calibration also up to 1000 Hz. They display the RMS value practically independent of the waveform - even with high harmonic content. Only with extreme waveforms (e.g. with phase-angle controls) and frequencies >100 Hz can the class accuracy no longer be maintained.
Due to their high self-consumption, the units are not suitable for connection to shunts or speed sensors. The units can be installed in control panels, mosaic grids or machines
Moving iron movement with sheath core system, silicone oil damping and spring-loaded tip bearings.