MTT MS3120 Terminal Block Type CT Transmitter

We received an enquiry from a customer measuring motor current through a CT, who needed that current reading to reach both a monitoring system and a separate protection relay. Splitting a CT’s output isn’t something you do casually — CT secondaries need proper handling, and the load on the circuit matters. What they actually needed was one clean current measurement, isolated and duplicated for two separate destinations.

The MTT MS3120 reads the AC current from a current transformer, calculates its true RMS value, and delivers it as two independent, isolated DC outputs from a single unit. This looks simple, but in actual application, loads driven by variable-frequency drives produce non-sinusoidal current waveforms, and a transmitter that only estimates average current can read wrong on that kind of load. True RMS calculation keeps the MS3120’s reading accurate regardless of waveform shape.

Full isolation between input, both outputs, and power keeps the transmitter safely separated from the monitored circuit while delivering clean, independent signals to every connected device. A choice of AC or DC power supply lets it fit panels without a dedicated low-voltage bus, and the DIN-rail housing mounts right where the CT wiring lands.

Before we quote, we would normally check: the CT’s secondary current range (0-1A or 0-5A), the output ranges needed on Output 1 and Output 2, the panel’s available power supply (AC or DC, and voltage), and whether the load has a non-sinusoidal waveform (VFD-driven, for example). Send us these details and we can confirm the right variant before you order. Hope this helps.