Rogowski Coils: Flexible Style Rope CTs

CTRC Series Rogowski Coils

Flexible Opening
Excellent Linearity
Low Phase Angle Error
Window Diameters: 3.1, 4.5, 7.5, or 12 Inches

Easier AC Current Measurement

The CTRC Rogowski coil current transformers are accurate, flexible, rope-like current sensors that can be connected around conductors. They greatly simplify AC current measurements of conductors where traditional split-core and solid-core CTs are difficult to use. With its flexible design, the CTRC is perfect for large bus bars and irregular-shaped conductor bundles. In addition, the coil’s small profile allows it to fit into tight spaces where rigid CTs won’t fit.

Fully Compatible with WattNode® Meters

Sold individually, the CTRC coils can be used for single-phase and three-phase services. The output of the CTRC’s flexible coil is connected to a conditioning circuit, where it is converted to a low-voltage (333.33 mVac) signal which is compatible with any WattNode meter.

Complete Solution

Four standard models are offered covering various conductor sizes and currents up to 6000 Amps. Non-standard currents ranges and window openings are available as custom orders. CTRC Rogowski coils are supplied with conditioning circuit pre-wire to coil and standard 8 ft. (2.4 m) black and white CT wires for connection to WattNode meter.

  • Safe: 333 mVac output at rated full scale current—no need for shorting blocks!
  • Low phase angle error: essential for accurate power and energy measurements
  • Approvals: UL Recognized, CE Mark, RoHS

Models

Model Rated
Amps
Coil
Diameter
MSRP
CTRC-03100-0250 250 3.15″ (8.0 cm) $181.50 each
CTRC-03100-0400 400 3.15″ (8.0 cm) $165.00 each
CTRC-03100-0600 600 3.15″ (8.0 cm) $181.50 each
CTRC-03100-1000 1000 3.15″ (8.0 cm) $181.50 each
CTRC-04500-1000 1000 4.5″ (11.4 cm) $170.00 each
CTRC-04500-1600 1600 4.5″ (11.4 cm) $187.50 each
CTRC-04500-2000 2000 4.5″ (11.4 cm) $187.50 each
CTRC-07500-1000 1000 7.5″ (19.0 cm) $192.50 each
CTRC-07500-1600 1600 7.5″ (19.0 cm) $192.50 each
CTRC-07500-2000 2000 7.5″ (19.0 cm) $175.00 each
CTRC-07500-3200 3200 7.5″ (19.0 cm) $192.50 each
CTRC-07500-4000 4000 7.5″ (19.0 cm) $192.50 each
CTRC-12000-2000 2000 12.0″ (30.5 cm) $218.90 each
CTRC-12000-3200 3200 12.0″ (30.5 cm) $218.90 each
CTRC-12000-4000 4000 12.0″ (30.5 cm) $199.00 each
CTRC-12000-5000 5000 12.0″ (30.5 cm) $218.90 each
CTRC-12000-6000 6000 12.0″ (30.5 cm) $218.90 each
  • List prices for quantity 1 to 30 pieces. Call for pricing on larger quantities.

A DC power supply is required for the CTRC conditioning circuit. The CTRC current transformers may be purchased with the following power supplies. One supply will power twelve conditioning circuits.

Power Supplies

Model Type Output
Voltage
Output
Current
MSRP
MDR-10-12 DIN-rail 12 Vdc 0.84 Amps $28.00 each

Specifications

  • Type: Flexible Rogowski coil current transformer with conditioning circuit

Electrical

  • Output wires: 8 feet (2.4 m), 22 AWG, white / black twisted
    • May be extended to 100 feet (30 m)
  • Optional: up to 100 feet (30 m)
  • Frequency: 50/60 Hz nominal
  • Maximum voltage: 600 Vac
  • Maximum safe amperage: >10,000A. Unlike conventional CTs, Rogowski coil CTs have negligible secondary current (typically less than one microamp) and very low secondary voltages (typically less than 100 mVac), so even during extreme overcurrent, the secondary voltage, current, and power dissipation will all be very low.
  • Measurement category: CAT III, 600 Vac
  • UL recognized: file number E344623 (PICQ2), UL standard 61010B-1

Accuracy

All measurements at 77°F (25°C) and 60 Hz unless otherwise noted.

  • Accuracy: ±1.0% of reading from 5% to 120% of rated primary current
  • Conductor position sensitivity: Additional error due to the location of the conductor within the coil

CTRC-Position-Accuracy.png

Family Center Edge Latch
CTRC-03100 No added error ±1.5% ±5.0%
CTRC-04500 No added error ±1.0% ±4.0%
CTRC-07500 No added error ±1.0% ±4.0%
CTRC-12000 No added error ±1.0% ±3.0%
  • External conductor sensitivity: ±2.0% of full-scale maximum (to clarify, if an external conductor carrying this CT’s rated current is just touching this CT, then the output of this CT may change by up to ±2.0% of the rated current)
    • CTRC-03100 models only: ±2.5% of full-scale maximum
  • Positioned at corner: ±1.0% maximum (if the CT is installed at a sharp bend of the conductor being measured)
    • CTRC-03100 models only: ±2.0% maximum
  • Additional error due temperature variation: ±1.5% from -4°F to 140°F (-20°C to 60°C)

Phase Angle

  • Phase angle: ±0.50 degrees (30 minutes) from 5% to 120% of rated current
  • Conductor position sensitivity: ±0.10 degrees max
  • External conductor sensitivity: ±0.25 degrees max
  • Positioned in corner: ±0.10 degrees maximum
  • Varying temperature: -4°F to 140°F (-20°C to 60°C): ±0.10 degrees

Conditioning Circuit

  • Output at rated amps: 333.33 mVac (one-third volt)
  • Maximum output: 1.3 Vac
  • Power requirements: 10 – 30 Vdc (12 Vdc or 24 Vdc recommended), 50 mA typical, 70 mA maximum

Environmental

  • Operating temperature: -4°F to 140°F (–20°C to 60°C)
  • Operating humidity: Non-condensing, 5 to 90% relative humidity (RH)
  • Pollution: POLLUTION DEGREE 2
  • Indoor use: Suitable for indoor use.
  • Outdoor use: Suitable for outdoor use when mounted in a NEMA 3R or 4 (IP 66) rated enclosure.

Specifications

  • Type: Flexible Rogowski coil current transformer with conditioning circuit

Electrical

  • Output wires: 8 feet (2.4 m), 22 AWG, white / black twisted
    • May be extended to 100 feet (30 m)
  • Optional: up to 100 feet (30 m)
  • Frequency: 50/60 Hz nominal
  • Maximum voltage: 600 Vac
  • Maximum safe amperage: >10,000A. Unlike conventional CTs, Rogowski coil CTs have negligible secondary current (typically less than one microamp) and very low secondary voltages (typically less than 100 mVac), so even during extreme overcurrent, the secondary voltage, current, and power dissipation will all be very low.
  • Measurement category: CAT III, 600 Vac
  • UL recognized: file number E344623 (PICQ2), UL standard 61010B-1

Warranty

5 Year limited warranty. See manual for details.