Current probe, high frequency wideband amps probe

A wide range of rugged clip around flexible coil current probes using Rogowski Coil technology for wide bandwidth measurement and faithful conversion of current to voltage, intended for use with oscilloscopes, data loggers, transient recorders, power meters and power analyzers. Based on the Rogowski principle, these probes give very high bandwidth performance and measurement of very high currents (10A-300kA). The small coil profile (typically 8mm dia), means the coil can be retrospectively installed without disruption to an active power system. As standard, the coil is insulated at 10kVrms, insulation can be increased if required. Models are available with a variety of clip-around coil sizes to suit most conductors, allowing easy current monitoring even where access is limited.

Bandwidth 1Hz to 16 MHz (see bandwidth spec for each model)
CWT LF models available with extended LF bandwidth <1Hz
Models covering a 10A - 300,000Amps range
0.2% accuracy
10kV Insulation capability
Optional Electrostatic screens
Flexible "clip-around" coil
±6V Instantaneous isolated output ideal for scopes, data loggers, PCI DAC cards and power analyzers
Uses 4 x AA batteries or 12V ac adapter (110V or 230Vac)
Traceable calibration certificate included
CE marked

Application	Typical uses
Power analyzers	Inexpensive method of extending the current, power and harmonic measurement range without bandwidth degradation. Excellent low frequency (0.5Hz) performance along with low phase shift
Motor drives and power electronic convertors	Allows measurement of gate turn on / turn off times and peak current
Motors and generator	Easy retrospective installation of probes around conductors where regular clamp and split core CTs are unsuitable
Induction heating	Measurement of high current / high frequency signals, including high order harmonic effects
Pulsed power applications	Semiconductor switches, capacitor discharge and circuit breaker interruption currents

CWT Specifications
Type	Sensitivity (mV/A)	Peak current (kA)	Peak di/dt (kA/mS)	Noise max^*1 (mV _pk-pk)	Droop typ. (%/ ms)	LF (3dB) bandwidth typ. (Hz) f_L	Phase lead at 50Hz typ. (deg)	HF (3dB) bandwidth typ. (MHz) f_H *²
Type	Sensitivity (mV/A)	Peak current (kA)	Peak di/dt (kA/mS)	Noise max^*1 (mV _pk-pk)	Droop typ. (%/ ms)	LF (3dB) bandwidth typ. (Hz) f_L	Phase lead at 50Hz typ. (deg)	^{Coil Length} ^300mm	^{Coil Length} ^700mm
High Sensitivity Ranges of CWT .... measuring currents from 300mA
CWT015	200.0	0.03	0.2	6.5	130	150	2.0@6kHz	6.0	5.5
CWT03	100.0	0.06	0.4	4.5	90	105	2.0@4kHz	8.5	7.5
CWT06	50.0	0.12	0.8	3.0	70	80	2.0@3kHz	12	8.5
CWT1	20.0	0.3	2.0	2.5	40	50	1.9@2kHz	16	10
CWT1N	20.0	0.3	2.0	2.0	20	25	1.9@1kHz	10	5
CWT3	10.0	0.6	4.0	8.0	3.0	3.5	1.0@300Hz	16	10
Standard Ranges of CWT .... measuring currents from 15A
CWT3N	10.0	0.6	4.0	14.0	0.9	1.0	1.7	10	5
CWT6	5.0	1.2	8.0	14.0	0.9	1.0	1.7	16	10
CWT15	2.0	3.0	20.0	7.0	0.7	0.8	1.3	16	10
CWT30	1.0	6.0	40.0	5.0	0.5	0.6	0.9	16	10
CWT60	0.5	12.0	40.0	3.5	0.35	0.4	0.6	16	10
CWT150	0.2	30.0	40.0	3.0	0.2	0.2	0.3	16	10
CWT300	0.1	60.0	40.0	3.0	0.1	0.1	0.2	16	10
CWT600	0.05	120.0	40.0	3.0	0.06	0.05	0.1	16	10
CWT1500	0.02	300.0	40.0	3.0	0.035	0.03	0.06	16	10

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

*2. The 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 f_H

TYPICAL ACCURACY

(full scale)

Calibrated 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
CWT 1N / 3N

all other CWT’s

PEAK 40.0

PEAK 20.0

PEAK 40.0

RMS 0.9 @ 70^oC

RMS 1.0 @ 70^oC

RMS 1.5 @ 70 ^oC (further information available on request)

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 (10kV insulation) 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 (^oC)	-20 to 100
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 Power adapter is included with the CWT probe, specify 230Vac or 115Vac. 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)
TEMPERATURE RANGE (^oC)		0^oC to +40^oC

Ordering	Type + ac adapter CWT unit is supplied with 12-24Vdc input as standard + 4 AA batteries and ac adapter, specify 115Vac or 230Vac	/	Cable length	/	Coil circumference	/	Insulation
e.g. order code = 6kApk, 4 AA Batteries, 12-24Vdc input, 115V ac adapter, 2.5 metre cable, 500mm coil and 10kV	CWT30 -B115	/	2.5	/	500	/	10
e.g. order code = 6kApk, 4 AA Batteries, 12-24Vdc input, 230V ac adapter, 4 metre cable, 300mm coil and 10kV	CWT30 -B230	/	4	/	300	/	10
e.g. order code = 1.2kApk, 4 AA rechargeable batteries, internal battery charger, 12-24Vdc input, 115V ac adapter, 2.5 metre cable, 500mm coil and 10kV	CWT6 -R115	/	2.5	/	500	/	10