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Your contact: +49 - 212 8804-0 • info@reo.de

Series WKO-2C

Double core technology closed-loop current transformers

Series WKO-2C

Unique Selling Point


  • High current measurement accuracy of 0.3%
  • Modular mounting plates providing universal mounting options 
  • Lower sensitivity to external magnetic fields
  • Bidirectional and isolated current measurement up to ±750A current output
  • Modular mounting plates
  • REO double core technology
  • All materials manufactured using UL listed materials

Description


REO has developed new generation of closed loop (C/L) current transducers which guarantees increased current measurement accuracy better than 0.3% in the whole frequency range: DC to 140 kHz.

The new current transducer type WKO-2C is a completely new development utilizing REO’s double core technology magnetic design. The unit uses the latest hall effect elements with an extended frequency response up to 120 kHz and accurate phase response.

Completely redesigned electronics ensures that the new C/L current transducer has better drift compensation and an extended temperature range from -40°C to 85°C.

  • According to: EN 50178:1997, UL 94-V0
  • Frequency range: (-3 dB) DC...140 kHz

Typical applications

  • Variable speed control of 3-phase AC-motor and servo motor drives
  • Industrial inverters
  • Uninterruptable power supplies
  • All types of switched mode power supplies
  • Power supplies for welding applications


Technical Data


  • Primary rated current : 500 - 2000 A
  • Messbereich : 0...3000 A
  • Frequency range : 120000 Hz

Mode of operation

Your contact: +49 - 212 8804-0 • info@reo.de

Series WKO-2C

Double core technology closed-loop current transformers

Technical data

Type

Primary RMS
Nominal-
current
IPN [A]

Measurement range
IP [A]

Feed-in
UC [V]

Measurement accuracy 
XG@Ipn
[-20…70°C]
von IPN [%]

ratio
KN

Secondary RMS
Nominalcurrent
m ISN [mA]

Secondary-
winding
Resistor
Rs@85°C  [Ω]

No-load
current
[mA]

WKO-2C-300

300

0 … ±2000

±11,4…25,2  < ±0,3 2000  150  13  26+IS

WKO-2C-500

500

0 … ±1000

±11,4…25,2

 < ±0,3

5000

100

76

 26+IS

WKO-2C-1000

1000

0 … ±2700

±14,25…25,2

 < ±0,3

5000

200

42

 26+IS

WKO-2C-2000

2000

0 … ±4000

±14,25…24

 < ±0,3

5000

400

26

 26+IS

 

Accuracy and dynamic data

Type

Linearity-
mistake


e [%]

Offset-
mistake@25°
IO [mA]

Offset Drift
-25°C …+70°C
IOT [mA]

Reaction time
tra[µs]

Response time
10%-90%
ta[µs]

dI/dt
[A/µs]

Band with
-1dB  [kHz]

WKO-2C-300

< ±0,1

< 0,5 < 25  200 400 400  120/150

WKO-2C-500

< ±0,1

< 0,5

< 25

200

400

400

120/150

WKO-2C-1000

< ±0,1

< 0,5

< 25

200

400

400

120/150

WKO-2C-2000

< ±0,1

< 0,5

< 25

200

1000

1000

150

 

Isolation data

Type

Creepage distance
dCp  [mm]

Clearance
dCi  [mm]

Creep resistance
[CTI]

AC-Isolation
test
50/60Hz 1min
Ud [kV]

Impulse voltage
test
1,2/50µs
Ui[kV]

Weight
[kg]

WKO-2C-300

14 13  600 6  12,5  0,340

WKO-2C-500

14

13

600

6

12,5

0,260

WKO-2C-1000

20

18

600

6

 12,5

0,700

WKO-2C-2000

35

30

600

6

 12,5

1,600

Your contact: +49 - 212 8804-0 • info@reo.de

Series WKO-2C

Double core technology closed-loop current transformers

Your contact: +49 - 212 8804-0 • info@reo.de

Series WKO-2C

Double core technology closed-loop current transformers

Your contact: +49 - 212 8804-0 • info@reo.de

Series WKO-2C

Double core technology closed-loop current transformers

Your contact: +49 - 212 8804-0 • info@reo.de

Series WKO-2C

Double core technology closed-loop current transformers

Maximum measuring resistance

Your contact: +49 - 212 8804-0 • info@reo.de

Series WKO-2C

Double core technology closed-loop current transformers

Dimension drawing

 

Dimensions

Your contact: +49 - 212 8804-0 • info@reo.de

Series WKO-2C

Double core technology closed-loop current transformers

REO - Double Core Technology

In most applications, C/L current transducers deal with measurements in the range from DC to mains frequencies 120kHz. For this purpose standard single core technology hall effect sensor mounted in the air gap is a good solution. 

In this design, the hall effect sensor located in the air gap, is used with a bipolar power stage to create an equal and opposite magnetic field in the core. This means that the current output signal is directly proportional to the measureable element on the conductor.

This principle works well for lower frequencies, but as frequencies increase the core inductivity becomes a larger factor and the compensating electronics are not able to function adequately. At this point, the unit acts like a conventional current transformer with poor linearity. This effect is demonstrated in Figure "Electronic and transformer phases are out of tune". This effect and subsequent lack of measurement accuracy is where the REO WKO 2C with double core technology is so important.

 

 

REO´s double core frequency response in Figure 4 shows the smooth path between electric and transformer domains.

We have tested other current transducer products and we can safely say that only a few of them have acceptable smooth frequency transition performance as shown in Figure "Comparison WKO-2C 500 and competitors products" below.