The MTT MS3920 Chassis-mounting CT Transmitter converts the AC current signal from a current transformer into a standard isolated DC output, giving switchgear and motor control panels a clean way to read line current into a PLC, indicator, or recorder. Its true-RMS operation keeps the reading accurate even on distorted, non-sinusoidal current waveforms, which matters increasingly as variable-frequency drives and other non-linear loads become common on the circuits being monitored.
Packaged in the compact chassis-mount format shared with the rest of the MS39-series for high-density installations on MTT’s RC3900 chassis platform, the MS3920 accepts a 0-1A or 0-5A AC input and can tolerate instantaneous overloads up to ten times its rated input for short-circuit conditions without damage. Dual output combinations of voltage and current are available to match the receiving equipment, front-accessible trimmers allow zero and span adjustment, and isolation between input, both outputs, and power keeps the transmitted signal free of noise and ground loops.
| Input Range | 0-1A AC, 0-5A AC, or custom up to 5A (50/60Hz) |
| Input Resistance | 5mΩ (5A) or 25mΩ (1A) shunt resistor |
| Max Input | 120% continuous; 10x rated input instantaneous (3s max) |
| Crest Factor | 3 max |
| Output Options | 1-5V DC, 0-5V DC, 0-10V DC, ±5V DC, ±10V DC, or 1-5V DC/4-20mA DC combinations |
| Output Load | 2mA max (voltage); 300Ω max (current) |
| Adjustment | ±2% of span, zero and span, via front trimmer |
| Accuracy | ±0.25% F.S. (min. 10% input, 25°C±5°C); ±0.2% span per 10°C temperature effect |
| Response Time | 0.4s max (0-90%, 100% step); adjustable option down to 80ms @90% |
| CMRR | 100dB min. (500V AC, 50/60Hz) |
| Isolation | Mutual isolation across input, outputs, and power; 100MΩ min. insulation resistance @500V DC; 1500V AC dielectric strength (input/other), 500V AC (outputs/power, 1 min) |
| Surge Withstand | Per ANSI/IEEE C37.90.1-1989 |
| Power Supply | 24V DC ±10%, 55mA max; 300mA fuse standard |
| Dimensions | W19.5 x H53 x D84mm |
| Weight | Approx. 70g |
| Mounting | Chassis mount, RC3900 mounting base required |
| Operating Conditions | 0-55°C, 90% RH max non-condensing |
| Storage Temperature | -10 to 60°C |
| Additional Features | Anti-humidity PCB coating; self pop-up wiring screws |
Frequently Asked Questions
What is the MTT MS3920 used for?
It converts the AC current signal from a current transformer into a standard isolated DC output, giving switchgear and motor control panels a clean way to read line current into a PLC, indicator, or recorder.
Does it handle distorted or non-sinusoidal current?
Yes, true-RMS operation keeps the reading accurate even on distorted waveforms, which matters increasingly as variable-frequency drives and other non-linear loads become common on monitored circuits.
What CT input does it accept?
0-1A or 0-5A AC, matching the standard secondary current ratings of common current transformers. Tell us your CT’s secondary rating and we can confirm the configuration.
Can it survive a short-circuit fault on the line being monitored?
Yes, the MS3920 can tolerate instantaneous overloads up to ten times its rated input for short-circuit conditions without damage, which matters since CT secondaries can see large fault currents.
How do I know if the MS3920 is right for my application?
If you need to transmit a CT’s current reading into a PLC or panel meter, with true-RMS accuracy and short-circuit tolerance, the MS3920 on an RC3900 base covers that. Send us your CT’s secondary rating and the output signal you need and we’ll confirm before you order.
Download MTT MS3920 Chassis-mounting CT Transmitter information here
Datasheet: MTT_MS3920_Datasheet
