CWTLF Rogowski Coil Current Probes: Precision Low-Frequency & High-Current Measurement
The CWTLF Rogowski Oscilloscope Current Probe is a specialized, shielded clip-on solution designed for precise alternating current (AC) measurements. Engineered for applications requiring extended low-frequency response, the CWTLF excels in capturing sub-Hertz levels while maintaining a broad bandwidth that reaches into the Megahertz range.
Whether you are performing power frequency analysis, harmonic measurements, or extended pulsed current testing, the CWTLF delivers stable phase response and minimal droop distortion.
What Is the CWTLF Rogowski Coil Current Probe?
The CWTLF is a flexible, clip-around current probe designed for low-frequency AC measurements where conventional current transformers (CTs) fall short. Unlike standard CTs, the CWTLF features an air-core design, meaning it is immune to magnetic saturation. This allows for accurate readings of:
- Strong fault currents
- Extended pulse durations
- Very low-frequency signals
Advanced Electrostatic Shielding
Equipped with a patented electrostatically shielded coil system, the CWTLF blocks high-voltage interference and fast-switching transient signals. This ensures high-fidelity measurements even in electrically noisy industrial environments.
Key Features of CWTLF Current Probes
➤ Wide Low-Frequency to High-Frequency Bandwidth
- Predictable phase response from sub-Hz to >100 kHz
- Wide-band (-3 dB) response from 0.008 Hz to >1 MHz (model-dependent)
- Suitable for both power frequency and high-frequency transient analysis
➤ Low Droop Distortion for Long Pulses
- Designed to accurately measure long-duration current pulses
- Ideal for pulsed power systems and fault current monitoring
➤ High Current Measurement Capability
- Current ratings from 300 A peak to 300 kA peak
- No saturation or performance loss at low frequencies
➤ Superior Electrical Immunity
- Electrostatically shielded Rogowski coils
- Excellent immunity to 50/60 Hz voltages and fast dV/dt transients
- Patented shielding technology for stable measurements
➤ Flexible & Non-Intrusive Design
- Clip-around Rogowski coil allows easy installation without breaking circuits
- Ideal for tightly packed busbars and hard-to-reach conductors
Technical Specifications
Output & Accuracy
- Output: ±6 V peak at rated peak current into ≥100 kΩ
(Recommended for 1 MΩ oscilloscope inputs) - Accuracy:
- ±0.2% of reading (conductor centered)
- ±1% typical due to conductor position
- Linearity: 0.05% of reading
- DC Offset: ±3 mV max at 25°C
- Not recommended for 50 Ω loads
Electrical & Environmental Ratings
- Coil Insulation: 10 kV peak (15 kV rms, 60 s withstand tested)
- Operating Temperature:
- Coil & cable: –20°C to +100°C
- Integrator electronics: 0°C to +40°C
- Removable silicone sleeve for enhanced mechanical protection
Coil, Cable & Power Options
- Standard circumferences: 300 mm, 500 mm, 700 mm, 1000 mm
- Custom coil lengths available on request
Cable Length Options
- 1 m, 2.5 m, or 4 m standard
- Extended cable lengths available on request
Battery Options
- Alkaline version: 4 × AA batteries (up to 70 hours)
- Rechargeable version: 4 × NiMH batteries (up to 30 hours)
- External power adapter (US / EU / UK / AUS) available
Leading Applications
The versatility of the CWTLF makes it the preferred choice across several critical industries:
Power & Harmonic Analysis: Ideal for 50/60 Hz measurements and identifying higher-order harmonics.
Fault & Protection Testing: Monitoring motor/generator faults and short-circuit currents.
Pulsed Power Systems: Precise measurement of energy storage discharge and long-duration pulses.
Power Electronics: Measuring AC ripple currents on high DC offsets—perfect for capacitor ripple and filter analysis.
Renewable Energy: Testing inverters and converters in EV and solar power systems.
Conclusion
If your application involves low-frequency AC currents, harmonics, long pulses, or high fault currents, the CWTLF Rogowski Coil Current Probe is a proven and dependable solution.
Its combination of wide bandwidth, low droop distortion, shielded design, and oscilloscope compatibility makes it a preferred choice for engineers seeking accurate and safe current measurement.
Pantronics India, an authorized distributor of Power Electronic Measurements (PEM), offers a range of Rogowski current sensors, including CWT, CWTHF, CWT Mini, and CWT Ultra-mini, featuring advanced technology for precise current measurement.
For engineers seeking accurate, wide-band Rogowski Coil Current Probes and professional application support in India, Pantronics India Pvt Ltd is your trusted partner
Frequently Asked Questions
The CWTLF Rogowski Oscilloscope Current Probe is used for low-frequency AC current measurement, including 50/60 Hz power analysis, harmonic measurements, long-duration pulses, and high fault or short-circuit currents.
Yes. The CWTLF provides a BNC output designed for oscilloscopes or data acquisition systems with an input impedance of 100 kΩ or higher, typically 1 MΩ oscilloscope inputs.
The CWTLF is optimized for high-impedance inputs. Using a 50 Ω load can significantly reduce signal amplitude and measurement accuracy, so it is not recommended.
The CWTLF offers:
● ±0.2% accuracy with the conductor centered
● ±1% typical variation due to conductor position
● 0.05% linearity, ensuring consistent performance over a wide current range
The CWTLF has an extended low-frequency response down to sub-Hz levels, making it suitable for very low-frequency AC currents, long pulses, and fault currents. It does not measure true DC, as Rogowski coils respond only to changing current.
Yes. The CWTLF is ideal for measuring small AC ripple currents even when a large DC current is present, such as in capacitor ripple monitoring and DC link applications.
The Rogowski coil is rated for 10 kV peak insulation and has been tested to withstand 15 kV rms at 50 Hz for 60 seconds, making it suitable for high-voltage environments.
CWTLF Rogowski Coil Current Probes are widely used in:
● Power electronics and inverter testing
● EV and renewable energy systems
● Industrial motor and generator testing
● Electrical protection and fault analysis
● R&D laboratories and test facilities
Expert Technical Support
CWTLF Rogowski Oscilloscope Current Probes at Pantronics India are supported by experienced application professionals for high-frequency, high-dV/dt power-electronics measurements.
Ms. Sunita Joshi
(Passive Components & Test & Measurement Expert)
Mail ID: s.joshi@pantronicsindia.com