CURRENT SENSORS

CTA3ph Flexible 5A Output Current Transformer

Suitable for meter monitoring in critical power environments

The CTA3ph three-phase Rogowski coil system delivers precise current measurement from 0–100A to 0–10,000A with 5A outputs and cable runs up to 70 ft (21.3 m).

Rated up to 7.5 VA, it supports energy metering and 5P10 / 5P20 protection relays.

Each kit contains three Rogowski probes, conditioners, cables, two PSUs, and DIN-rail mounting, supplied fully pre-wired for rapid installation.

The CTA3ph three-phase flexible current transformer is a Rogowski coil–based current sensing system designed to deliver a standard 5A output (up to 5VA) for direct connection to conventional 5A metering circuits and protection relays such as 5P10 and 5P20. Its flexible clip-around design enables quick installation around existing busbars or feeder cables without disconnecting conductors.

Unlike traditional iron-core current transformers, the Rogowski coil design eliminates open-circuit risks and allows installation without interrupting the LV electrical supply. This makes the CTA3ph particularly well suited to retrofit energy monitoring and power measurement projects where system downtime must be avoided.

Available measurement ranges extend from 100A to 10,000A, providing accurate current monitoring across a wide range of electrical distribution systems. The lightweight flexible sensor easily wraps around cables, even in restricted panel spaces.

CTA3ph systems are commonly used in data centres, hospitals, financial institutions, and commercial buildings, where reliable power monitoring and energy management are critical.

CTA3ph Flexible Rogowski Current Probe – Technical Specifications

Current Sensor (Rogowski Coil)

Type: Rope-type flexible Rogowski coil with clip-around installation
Sensor Diameters:
- 100 mm (3.85")
- 160 mm (6.2")
- 220 mm (8.6")
- 330 mm (11.7")
Construction: Split-core / wrap-around flexible coil
Sensor Thickness: 8 mm (0.31")
Material: Flame-retardant thermoplastic rubber, UL94V0 rated
Working Voltage: 1000 V, 50/60 Hz, CAT III
Dielectric Test: 7400 V, 50/60 Hz for 1 minute

Connection Cable

Cable Type: UL Style 20940
Voltage Rating: 1000 V
Diameter: 5 mm
Standard Lengths: 3 m, 5 m, and 10 m

Conditioner / Amplifier Module

Input Current Ranges: 0–100 A up to 0–10,000 A RMS
Accuracy Options (10–125% range):
- <0.25%
- <0.5%
- <1.0%
Housing: DIN-rail mounted module, UL94V0 / CSA-approved polycarbonate
Fundamental Frequency Range: 20 Hz – 1500 Hz
Bandwidth: 20 Hz – 1500 Hz
Phase Shift: <0.04° at 50 / 60 / 400 Hz
Input Impedance: 100 kΩ
Waveform Crest Factor Capability: 1.4 – 5

Output Characteristics

Output Signal: Calibrated 0–5 A RMS
Output Ratings:
- 2.5 VA (0.1 Ω burden)
- 5 VA (0.2 Ω burden)
- 7.5 VA
Supplied as: Calibrated sensor and conditioner set with traceable calibration

Monitoring & Protection

Status Indicators: Health monitoring LEDs
Fault Output: Relay contact for fault reporting

Power Supply

Standard Supply: 110–240 VAC
Optional Supplies: 24 VDC, 48 VDC, 125 VDC
Instrument Fuse: 1 A slow-blow (time delay) for 230/240 VAC supply

I

ncluded with CTA3ph Kits

Flexible Rogowski current probes
Signal conditioning module
Output transformer (5 A)
Power supplies
DIN-rail mounting hardware

Environmental

Operating Temperature: –20 °C to +65 °C

Compliance & Approvals

Products are manufactured in accordance with relevant CE, IEC, EN, ASME, and BS standards, with materials approved to UL and CSA safety requirements.

Applications & Benefits

Rapid installation in critical facilities including hospitals, data centres, airports, shopping centres, and financial institutions
Installs without shutting down the LV electrical supply, helping avoid costly operational downtime
Ideal for retrofit energy monitoring projects in existing electrical infrastructure
Compatible with energy management systems and legacy 5A metering circuits
Suitable for power, energy, and current monitoring in solar and renewable installations
Designed for active harmonic filter systems, where fast response and higher burden capability are required
Effective for power quality monitoring and harmonic cancellation applications
Flexible Rogowski coil design easily wraps around busbars or feeder cables
Lightweight and durable UL-rated sensor construction for long-term reliability
Suitable for permanent or semi-permanent installations
Ideal where conventional iron-core CTs are too large or impractical to install

CTA3ph 5A Rogowski Coil – Key Facts

Flexible Rogowski coil current sensing technology with calibrated 5A RMS output
Designed for three-phase power systems in environments such as data centres, banks, and commercial buildings
Available coil diameters: 100 mm, 150 mm, 200 mm, and 330 mm
Isolated measurement output connects directly to kWh energy meters and monitoring systems
Output ratings available at 2.5 VA, 5 VA, or 7.5 VA
Measurement accuracy options: 0.25%, 0.5%, or 1%
Wide measurement range: 1% to 125% of rated current
Flat frequency response: 25 Hz – 1500 Hz
Long-distance transmission capability: up to 500 m (1640 ft) for 0–5 A signals

Electrical & Safety Information

Continuous insulation rating: 1 kV Rogowski coil sensor
Dielectric test: 7.4 kV
Power supply: 110–240 VAC standard
Optional power inputs: 24 VDC, 48 VDC, or 125 VDC
Operating temperature: –20 °C to +45 °C (sensor up to +80 °C)
Safety compliance: EN61010-1
- 1000 VAC CAT III
- 600 VAC CAT IV
Materials: UL94V0 flame-retardant construction
Certification: CE marked with supplied calibration certificate and accreditation documentation

Installation Advantages

Fast clip-around installation on busbars or feeder cables
Suitable for live installations without interrupting the LV supply
Ideal for retrofit metering and monitoring applications
Lightweight and flexible sensor design for confined electrical panels

Kit includes 3x current probe, cables, conditioners, psus, Din-Rail
Use for Metering and 5P10 / 5P20 Protection
Flexible Three Phase Rogowski Coil AC current probes for current sensing
Uses Flexible Core 5A Rogowski Coil sensing technology, UV resistant insulation
Compact high accuracy sensors from 1% to 125% of range
Flexible Rogowski Coil Current Sensors will fit in tight spaces
Split core clip-together Rogowski Coil current probes for fast installation
Quick fitting capability allows for live installs reducing shutdown period
Available ratings 2.5VA, 5VA or 7.5VA
Options for very-long 'sensor to metering' distances
Relay contacts for health reporting

CURRENT SENSORS

CTA3ph Flexible 5A Output Current Transformer

Suitable for meter monitoring in critical power environments

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