Flexible Rogowski Current Transformer

• Flexible Opening
• Excellent Linearity
• Low Phase Angle Error
• Window Diameters: 3.1, 4.5, 7.5, or 12 Inches
• From 250 to 6000 Rated Amps

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 are available as custom orders.

• Safe: burden resistor built-in, 333 mVac voltage output at rated full scale current, no shorting blocks needed
• Low phase angle error: essential for accurate power and energy measurements
• Approvals: UL Recognized, CE Mark, RoHS

 

CTRC Current and Superseded Models
Model	Superseded Models	Rated Amps	Coil Diameter
CTRC-03100-0400		400	3.15″ (8.0 cm)
RCLL-4.7-1000	CTRC-04500-1000	1000	4.5″ (11.4 cm)
CTRC-07500-2000		2000	7.5″ (19.0 cm)
CTRC-12000-4000		4000	12.0″ (30.5 cm)
Non-Stock Models (Call for pricing)
CTRC-03100-0250		250	3.15″ (8.0 cm)
CTRC-03100-0600		600	3.15″ (8.0 cm)
CTRC-03100-1000		1000	3.15″ (8.0 cm)
CTRC-04500-1500		1500	4.5″ (11.4 cm)
CTRC-04500-2000		2000	4.5″ (11.4 cm)
CTRC-07500-1000		1000	7.5″ (19.0 cm)
CTRC-07500-1500		1500	7.5″ (19.0 cm)
CTRC-07500-3000		3000	7.5″ (19.0 cm)
CTRC-07500-4000		4000	7.5″ (19.0 cm)
CTRC-12000-2000		2000	12.0″ (30.5 cm)
CTRC-12000-3000		3000	12.0″ (30.5 cm)
CTRC-12000-5000		5000	12.0″ (30.5 cm)
CTRC-12000-6000		6000	12.0″ (30.5 cm)

 

• 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

 

Family	Centre	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 the 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
• CTRC Power requirements: 10 – 30 Vdc (12 Vdc or 24 Vdc recommended), 50 mA typical, 70 mA maximum
• RCSL/RCLL Power Requirements: 3.5 Vdc to 13.5 Vdc (5 Vdc or 12 Vdc recommended), 6 mA typical, 20 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.

Warranty

5 Year limited warranty. See manual for details.

Safety Note

Warning: Hazardous Voltages – Only qualified personnel or licensed electricians should install the WattNode meter and current transformers.