The MTT MS3720-01 is a fast response version of the plug-in CT transmitter, built for applications where current readings need to keep up with rapidly changing loads. It responds to a step change in as little as 20ms, a large step up from the standard model, making it well suited to protection schemes, fast-cycling equipment, and control loops that need an up-to-date current reading rather than a smoothed, lagging one.
Like the standard model, it reads the AC output of a current transformer, calculates its true RMS value, and converts it into a standard DC signal, with both 1A and 5A CT input ranges and a choice of current or voltage outputs. A second isolated output is available for feeding an independent monitoring or alarm system, and it clips into its own plug-in socket base for fast swap-out during calibration or maintenance. Flexible AC or DC power plus wall or DIN rail mounting make it easy to fit into an existing panel.
| Input Range | 0-1A AC or 0-5A AC, 50/60Hz (sine wave) |
| Output | 0-20mA or 4-20mA DC current; 10mV to 20V DC voltage; single or dual output |
| Response Time | 20ms max. (0-90%, step input at 100%) |
| Accuracy | Better than ±0.25% of span (at 25°C±5°C) |
| Temperature Effect | Better than ±0.2% of span per 10°C change |
| Output Ripple | Less than 0.5%p-p of span |
| Isolation | 4-way isolation between input, output 1, output 2, and power |
| Insulation Resistance | 100MΩ min. at 500V DC |
| Dielectric Strength | 2000V AC for 1 minute |
| Power Supply | 100-240V AC (50-60Hz), 24V DC, or 100-240V DC |
| Dimensions | W29 × H86 × D125mm |
| Weight | 120g max. (main unit), plus 80g max. socket |
| Mounting | Wall or DIN rail mounting |
| Terminals | M3.5 screw terminals |
| Operating Temperature | -5 to 55°C |
| Operating Humidity | 5 to 90% RH, non-condensing |
Frequently Asked Questions
What is the MTT MS3720-01 used for?
It’s a fast response CT transmitter. Like the standard MS3720, it reads a current transformer’s AC output and converts it to a standard DC signal, but it responds to a step change in as little as 20ms, so it’s suited to protection schemes and fast-cycling loads that need an up-to-date current reading.
What’s the difference between the MS3720-01 and the standard MS3720?
The MS3720-01 responds much faster to a change in current — 20ms versus the slower response of the standard model — at the cost of a bit more output ripple. Choose the MS3720-01 when your application needs to react to fast load changes; choose the standard MS3720 for general monitoring where a smoother, more damped reading is preferred.
What CT input ranges does the MS3720-01 support?
Both 1A and 5A CT secondary ranges are available. Tell us your CT’s secondary rating and we can confirm the right input range at order.
Can the MS3720-01 provide two separate outputs?
Yes — a second isolated output is available, so the current reading can feed a fast protection loop and a separate monitoring system at the same time.
How do I know if I need the fast response version?
If your application involves rapidly changing loads or needs a quick-reacting protection signal, the MS3720-01 is the right choice. Send us your CT rating and response requirement and we can confirm.
Download MTT MS3720-01 Slim Plug-In Fast Response CT Transmitter information here
Spec Sheet: SpecSheet1_MS3720-01_Rev130_E.pdf
Manual: Manual1_MS3720-01_Rev110_E.pdf
