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CWT and CWT LF Wideband and split core current probes for high frequency high current measurement - Many stocked, please inquire for the closest model

The CWT current sensors are 1Hz-20MHz rugged clip-on flexible coil wideband current probes, these work with any Data Aquisition (DAQ), scope or virtual oscilloscope.

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cwt
  • Bandwidth 1Hz to 16 MHz (see bandwidth spec for each model)
  • CWT LF models available with extended LF bandwidth and low phase shift<1Hz
  • Models covering a 0.5A - 1200kA Amps range
  • 300:1 measuring range, example 300A CWT1B probe will measure 1A
  • 0.2% accuracy
  • 10kV Insulation capability
  • Optional Electrostatic screens for HV and noisy systems
  • Flexible "clip-on" split core coil
  • ±6V Instantaneous isolated output ideal for scopes, data loggers, PCI DAC cards, power analyzers
  • Uses 4 x AA batteries or 12V ac adapter (110V or 230Vac)
  • Traceable calibration certificate included
  • CE marked
  • Wide variety of models in stock

The CWT current sensors are rugged clip-on flexible coil wideband current probes, based on tried and tested Rogowski Coil technology for wide bandwidth measurement and perfect conversion of current to voltage, intended for use with oscilloscopes, data loggers, transient recorders and power analyzers - ideally suited for power electronic applications. Based on the Rogowski principle, these probes have intrinsic high bandwidth performance and wide dynamic range allowing measurement of both small and large currents (1A-600kA) from 0.01Hz to 20MHz. The small coil profile (8mm dia), means the coil can be retrospectively installed without disruption to active power systems. As standard, the coil is insulated at 10kVrms, insulation can be increased if required. Models are available with a range of clip-around coil sizes to suit most conductors, allowing easy current monitoring even where access is limited.

Selection table for CWT range - these current probes have full 300:1 range

CWT Specifications
Type Sensitivity
(mV/A)		 Peak current Peak di/dt
(kA/uS)		 Noise max*1
mV pk-pk		 Droop
typ.
(%/ ms)		 LF (3dB)
bandwidth
typ. (Hz) fL		 Phase Lead
Degrees		 HF (3dB) bandwidth
typ. (MHz) fH*2
Coil Length
300mm		 Coil Length
700mm
High Sensitivity Ranges of CWT .... measuring currents from 300mA
CWT015 200.0 0.1A to 30A 0.2 6.5 130 150 2.0@6kHz 6 4
CWT03 100.0 0.2A to 60A 0.4 4.5 90 105 2.0@4kHz 10 6.5
CWT06 50 0.4 to 120A 0.8 3.0 70 80 2.0@3kHz 16 10
CWT1 20.0 1A to 300A 2.0 2.5 40 50 1.9@2kHz 16 10
CWT1N 20.0 1A to 300A 2.0 2.0 20 25 1.9@1kHz 10 5
CWT3 10.0 2A to 600A 4.0 8.0 3.0 3.5 1.0@300Hz 16 10
High Sensitivity Ranges of CWT .... measuring currents from 300mA
CWT3N 10 2A to 600A 4.0 14.0 0.9 1.0 1.7 10 5
CWT6 5.0 4A to 1.2kA 8 14.0 0.9 1.0 1.7 16 10
CWT15 2.0 10A to 3kA 20.0 7.0 0.7 0.8 1.3 16 10
CWT30 1.0 20A to 6kA 40.0 5.0 0.5 0.6 0.9 16 10
CWT60 0.5 0.04kA to 12kA 40.0 5.0 0.5 0.6 0.9 16 10
CWT150 0.2 0.1kA to 30kA 40.0 3.0 0.2 0.2 0.3 16 10
CWT300 0.1 0.2kA to 60kA 40.0 3.0 0.1 0.1 0.2 16 10
CWT600 0.05 0.4kA to 120kA 40.0 3.0 0.06 0.05 0.1 16 10
CWT1500 0.02 1kA to 300kA 40.0 3.0 0.035 0.03 0.06 16 10
CWT3000 0.01 2kA to 600kA 40.0 3.0 0.035 0.03 0.06 16 10
CWT6000x 0.005 4kA to 1200kA 40.0 3.0 0.035 0.03 0.06 16 10

*1Distributed around the fL (3dB) bandwidth. Additional 50/60Hz noise of approximately 2mVpk-pk applies with AC 115V and 230V supplied CWT

*2The high frequency bandwidth is in part dependent on coil length. The values given are for a 700mm coil, a 300 –or- 500mm coil will have a higher fH

TYPICAL ACCURACY
(full scale)
Calibrated & traceable to UKAS ±0.2% with conductor central in the loop
Variation with conductor position in the coil loop typically ±1%
TYPICAL LINEARITY
±0.05% (full scale)
ABSOLUTE MAXIMUM VALUES OF di / dt (kA/µs)
(value must not be exceeded)
CWT 015, 03, 06
PEAK 40.0
RMS 0.9 @ 70℃
CWT 1N / 3N
PEAK 20.0
RMS 1.0 @ 70℃
all other CWT's
PEAK 40.0
RMS 1.5 @ 70 ℃ (further information available on request)

Application

Typical uses

Power analyzers
Convenient method of extending the current, power and harmonic measurement range without bandwidth degradation. Excellent low frequency (0.06Hz) performance along with low phase shift <0.2deg
Motor drives and power electronic converters
Allows measurement of GaN, IGBT switching times, gate turn-on/turn-off times and peak current
AC Motors and generators, diagnostics, testing and installation
Easy retrospective installation of probes around conductors where regular clamp and split core CTs will not fit
Induction heating current control and diagnosis
Measurement of high current / high frequency signals, including high order harmonic effects
GaN and pulsed current applications
Semiconductor switches: IGBT, Power MOSfets, capacitor discharge and circuit breaker interruption currents
Capacitor discharge and lightning strike research
Measurement of transient and repetitive peak currents without opening conductors
Coil and cable
COIL CIRCUMFERENCE ‘A’ (mm)
300, 500, 700 or 1000mm
COIL CROSS SECTION ‘B’ (mm)
(dependent on "Peak coil voltage isolation" see below)
8.5 (supplied with 10kV insulation as standard)
14.0 (with protection sleeve)
PEAK COIL VOLTAGE ISOLATION (kV)
10

Safe peak working voltage to earth. The coils are flash tested at 15kVrms for 60 seconds. The coil is supplied with a removable silicone sleeve which provides additional mechanical protection.

TEMPERATURE RANGE (℃)
-20°C to 100°C

For de-rating due to temperature cycling please consult Powertek

CABLE LENGTH (metre) (from box to coil)
2.5 or 4
Power input - mechanical - environmental
Power Supply
All CWT units are supplied with four AA batteries (typical life 90 hours) and a 12V-24Vdc input socket
A Universal Power adapter is included with the CWT probe (accepts 115Vac or 230Vac)
Rechargeable batteries and internal charger, option R, is available. (batteries are charged whenever external +12-24V dc supply is present). Typical recharge time 40 hrs, typical life 8 hrs.
INTEGRATOR BOX DIMENSIONS (mm)
H =183mm, W = 93mm, D = 32mm
OUTPUT SOCKET
BNC (output impedance 50 ohms- unit supplied with 0.5m BNC-BNC coaxial cable)
MIN. OUTPUT LOADING
100kohm (for rated accuracy), 50ohm drive capability optional.
TEMPERATURE RANGE (℃)
0℃ to +40℃
Ordering
Model
CWT unit is supplied with bnc-bnc cable, 12-24Vdc input, 4 AA batteries, power adapter and user manual, calibration certificate and carry case.
Cable length (m)
Coil circumference (mm)
e.g. order code = 6kApk, 4 AA Batteries, 12-24Vdc input, ac adapter, 2.5 metre cable, 500mm coil (Coil insulation is 10kV as standard)
CWT30B
2.5
500
e.g. order code = 6kApk, 4 AA Batteries, 12-24Vdc input, 230V ac adapter, 4 metre cable, 300mm coil
CWT30B
4
300
e.g. order code = 1.2kApk, 4 AA rechargeable batteries, internal battery charger, 12-24Vdc input, ac adapter, 2.5 metre cable, 500mm coil
CWT6R
2.5
500

All CWT current probes are supplied with bnc-bnc cable, 12-24Vdc input, 4 AA batteries, power adapter and user manual, calibration certificate and carry case. If you have any queries regarding the CWT or require specifications outside our standard ranges please do not hesitate to contact us.

Powertek specializes in the design and manufacture of electrical power, voltage and current measuring instrumentation
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