CWT Ultra miniature wideband current probe for ac current measurement

Powertek
UK Tel: +44 1788 519911
US Tel: +1 631 744 0294
Email : info@powertekuk.com

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The CWT ULTRA Miniature current probes utilize a Rogowski Coil sensor thin enough (typical cross section 1.7mm) to fit between the legs of a T0220 semiconductor device.   With high frequency bandwidths up to 20MHz, the CWT ULTRA miniature is ideal for measuring steady state, switching transients or pulsed currents between 300mA and 1200Apk in power electronic equipment.  The CWT ULTRA miniature 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.   All models are supplied with an 80mm length clip-around coil, ensuring easy current monitoring even where access is limited.

 

cwtultra.jpeg (7485 bytes)

Sense coil thickness 1.7mm

 
  • 1.7mm dia sense coils will fit between the legs of T0220 package

  • Very thin & flexible clip-around sense coil

  • Peak Current ratings from 30Apk to 1200Apk

  • Sensitivity set to give ± 6 volts peak output
    (e.g. 20.0mV/A for ± 300A peak)

  • Capability of driving 50 ohm impedance

  • High Frequency Bandwidths 10Hz to 20MHz

  • Accuracy typically 0.2% of reading

  • Sense coil length of 80mm

  • Peak voltage isolation 1.2kV

 

umferrule.jpg (16818 bytes)

Ultra mini probe tip and ferrule dimensions



Models

CWT015 200mV/A 30Amax 116Hz to 20MHz       order code CWT015 B / 1 / 80UM
CWT03 100mV/A 60Amax 66Hz to 20MHz      order code CWT03 B / 1 / 80UM
CWT06 50mV/A 120Amax 32Hz to 20MHz      order code CWT06 B / 1 / 80UM
CWT1 20mV/A 300Amax 9.0Hz to 20MHz      order code CWT1 B / 1 / 80UM
CWT3 10mV/A 600Amax 6.2Hz to 20MHz      order code CWT3 B / 1 / 80UM
CWT6 5mV/A 1200Amax 3.2Hz to 20MHz      order code CWT6 B / 1 / 80UM

Cable length - The cable connecting the measurement coil to the integrator box is 1m

Get CWT Ultra mini .pdf data



Selection table for CWT Ultra mini range

CWT Ultra Mini specifications
Type Sensitivity

(mV/A)

Peak current

(A)

Peak di/dt

(kA/mS)

 

 

Noise max*1

(mVpk-pk)

Droop

typ.

(%/ us)

LF (3dB) bandwidth typ. (Hz) fL Phase lead at 1kHz

typ. (deg)

HF (3dB) bandwidth typ. (MHz) fH *2
Coil Length 80mm
High Sensitivity Ranges of CWT .... measuring currents from 300mA
CWT015 200.0 30 1.0 20 0.100 116 8.4 20
CWT03 100.0 60 2.0 15 0.060 66.5 4.2 20
CWT06 50.0 120 4.0 12 0.030 32 2.1 20
CWT1 20.0 300 10.0 10 0.009 9.0 0.7 20
CWT3 10.0 600 20.0 10 0.006 6.2 0.7 20
CWT6 5.0 1200 40.0 10 0.004 3.2 0.7 20

*1. Distributed around the fL (3dB) bandwidth. 
*2. The high frequency bandwidth is in part dependent on coil length.   Contact Powertek for values of fH for other coil lengths. 

TYPICAL ACCURACY

(full scale)

Calibrated to UKAS ±0.2% with conductor central in the loop

Variation with conductor position in the coil loop typically ±2%

TYPICAL LINEARITY ±0.05% (full scale)
ABSOLUTE MAXIMUM VALUES OF di / dt (kA/µs)

(value must not be exceeded)

CWT 015, 03  
CWT 06, 1
CWT3, 6
PEAK  25.0
PEAK  25
.0
PEAK 40.0
RMS  1.0 @ 70oC
RMS 2.0
@ 70oC
RMS 2.2 @ 70oC


Coil and cable

COIL CIRCUMFERENCE ‘A’ (mm) 80mm
COIL CROSS SECTION ‘B’ (mm) 1.7mm
PEAK COIL VOLTAGE ISOLATION (kV) 1200V
Safe peak working voltage to earth. Coils are flash tested at 3kV/60Hz for 60 seconds.  Information about the continuous use of coils at high voltage can be obtained from Powertek
TEMPERATURE RANGE (oC) -10oC to 70 oC
For de-rating due to temperature cycling please consult Powertek
CABLE LENGTH (metres) (from box to coil) 1m   



Power input - mechanical - environmental
POWER SUPPLY

 

All CWT Ultra Mini units are supplied with four AA batteries (typical life 90 hours) and a 12V-24Vdc input socket and a power adapters to power the CWT from 230Vac or 115Vac.  Specify adapter type, 230Vac  or 115 Vac
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 will reduce the sensitivity to half its normal value (for driving long cables >10m)
TEMPERATURE RANGE (oC) 0oC to 40 oC

 

Ordering Type + ac adapter

CWT Ultra mini unit is supplied with 12-24Vdc input as standard + 4 AA batteries.   Specify ac power adapter option:- 115Vac or 230Vac 

/ Cable length / Coil circumference
e.g. in this example CWT order code = 30Apk model CWT015-B /

1

/

80UM

All CWT current probes are supplied with hard carry case, bnc-bnc cable, batteries, power adapter, user manual, statement of conformance & calibration certificate

If you have any queries regarding the CWT Ultra Mini or require specifications outside our standard ranges please do not hesitate to contact us.

CE marked

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