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CWT Mini Clip On High Frequency Current Probe
Rogowski Coil Current Sensor - Miniature High Frequency Probe
The CWT Miniature current probes utilize a Rogowski Coil sensor thin enough (typical cross section 3.5mm) to fit in very confined spaces - often between the legs of a semiconductor power switching device. With high frequency bandwidths up to 20MHz, the CWT miniature Rogowski coil is ideal for measuring switching transients or pulsed currents starting at 300mA up to 300kA in power electronic equipment. The CWT miniature Rogowski probe is a clip around flexible coil current probe based on the Rogowski principle to achieve high bandwidth measurement and faithful conversion of current to voltage, intended for use with oscilloscopes, data loggers, power meters and power analyzers. Available with a 100mm or 200mm length clip-around coil, ensuring easy current monitoring even where access is limited.
CWT Mini Rogowski Coil
The CWT miniature Rogowski coil range from Powertek, combines state of the art performance of the CWT ac current probe but features a miniature clip around Rogowski coil capable of monitoring currents in even the most difficult to reach parts of the circuit.
Full specifications for the CWT Miniature Rogowski coil
range are available in the
CWTmini datasheet
Available kA Peak Current ratings 0.03, 0.06, 0.15, 0.3, 0.6, 3.0, 6.0, 12, 30, 60, 120, 300
Sensitivity set to give ± 6 volts peak output (e.g. 1.0mV/A for ± 6000A peak)
Typical Bandwidth 0.1Hz to 17MHz
Accuracy typically 2% of reading
DC offset no greater than 2mV
Thin - flexible - clip-around coils
- Coil lengths of 100 and 200mm
- Rogowski Coil cross sectional diameter 3.5mm for 2kV isolation and 4.5mm for 5kV isolation
- Peak voltage isolation either 2kV or 5kV
Cable length - The cable connecting the cable to the integrator box comes in lengths from 1m to 4m.
Integrator power supply
- Either Battery 4 AA 1.5V standard alkali batteries typical life 70hrs plus- 2.1mm/2.5mm socket for 12 to 24V DC input (batteries inoperative when DC supply present)
or Rechargeable NiMH Batteries typical life 30hrs
plus - 2.1mm/2.5mm socket for 12 to 24V DC input (batteries trickle charged when DC supply present)
An AC/DC adapter is included for use with the CWT details can be found in Euro_adapter.pdf, UK_adapter.pdf and USA_adapter.pdf.
CE marked
Selection Table for CWT Mini Clip On Current Probes
| CWT Mini Rogowski Coil Specifications | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Type | Sensitivity (mV/A) |
Peak current (kA) |
Peak di/dt (kA/uS) |
Noise max*1 mV pk-pk |
Droop typ. (%/ ms) |
LF (3dB) bandwidth typ. (Hz) fL |
Phase lead at 50Hz typ. (deg) |
HF (3dB) bandwidth typ. (MHz) fH*2 |
Coil Length 100mm |
Coil Length 200mm |
| High Sensitivity Ranges of CWT .... measuring currents from 300mA | |||||||||
| CWT015 | 200.0 | 0.03 | 0.2 | 6.5 | 130 | 150 | 2.0@6kHz | 5.0 | 3.5 |
| CWT03 | 100.0 | 0.06 | 0.4 | 4.5 | 90 | 105 | 2.0@4kHz | 8.5 | 5.5 |
| CWT06 | 50.0 | 0.12 | 0.8 | 3.0 | 70 | 80 | 2.0@3kHz | 17 | 12 |
| CWT1 | 20 | 0.3 | 2.0 | 2.5 | 40 | 50 | 1.9@2kHz | 17 | 12 |
| CWT3 | 10.0 | 0.6 | 4.0 | 8.0 | 3.0 | 3.5 | 1.0@300Hz | 17 | 12 |
| Standard Ranges of CWT .... measuring currents from 15A | |||||||||
| CWT6 | 5.0 | 1.2 | 8.0 | 14.0 | 0.9 | 1.0 | 1.7 | 17 | 12 |
| CWT15 | 2.0 | 3.0 | 20.0 | 7.0 | 0.7 | 0.8 | 1.3 | 17 | 12 |
| CWT30 | 1.0 | 6.0 | 25.0 | 5.0 | 0.5 | 0.6 | 0.9 | 17 | 12 |
| CWT60 | 0.5 | 12.0 | 25.0 | 3.5 | 0.35 | 0.4 | 0.6 | 17 | 12 |
| CWT150 | 0.2 | 30.0 | 25.0 | 3.0 | 0.2 | 0.2 | 0.3 | 17 | 12 |
| CWT300 | 0.1 | 60.0 | 25.0 | 3.0 | 0.1 | 0.1 | 0.2 | 17 | 12 |
| CWT600 | 0.05 | 120.0 | 25.0 | 3.0 | 0.06 | 0.05 | 0.1 | 17 | 12 |
| CWT1500 | 0.02 | 300.0 | 25.0 | 3.0 | 0.035 | 0.03 | 0.06 | 17 | 12 |
*1Distributed around the fL (3dB) bandwidth.
*2The high frequency bandwidth is in part dependent on coil length. Contact Powertek for values of fH for other coil lengths
Variation with conductor position in the coil loop typically ±2%
(value must not be exceeded)
4.5mm for 5kV isolation
Safe peak working voltage to earth. 2kV coils are flash tested at 3.8kV/60Hz for 60 seconds and 5kV coils are flash tested at 8kVrms/60Hz for 60 seconds. Information about the continuous use of coils at high voltage can be obtained from Powertek
For de-rating due to temperature cycling please consult Powertek
Max cable length for CWT015 is 1m, CWT03 is 1.5m, CWT06 is 2.5m
and a power adapter (AC to 12vDC), to power the CWT from 230Vac or 115 Vac. Specify adapter type 230V or 115V
Rechargeable batteries, option R, are available. (batteries are charged whenever external +12-24V dc supply is present). Typical recharge time 40 hrs, typical life 8 hrs.
| Ordering | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Model: CWT mini unit is supplied with bnc-bnc cable, 12-24Vdc input, 4 AA batteries, power adapter, user manual, calibration certificate and carry case. |
Power Option: B-Battery R-Rechargeable |
Cable length (m) | Coil circumference (mm) | Insulation (kV) | |||||
| e.g. order code 30Apk, 4 AA Batteries, ac adapter, 12-24Vdc input, 1metre cable, 100mm coil, 5kV insulation | CWT mini 015 | B | 1 | 100 | 5 | ||||
| e.g. order code 6kApk, 4 AA Batteries, ac adapter, 12-24Vdc input, 2.5 metre cable, 200mm coil, 2kV insulation | CWT mini 30 | B | 2.5 | 200 | 2 | ||||
| e.g. order code 120Apk, 4 x AA rechargeable Batteries, internal battery charger, ac adapter, 12-24Vdc input, 2.5metre cable, 100mm coil length and 5kV isolation | CWT mini 06 | R | 2.5 | 100 | 5 | ||||
If you have any queries regarding the CWT or require specifications outside our standard ranges please do not hesitate to contact us.