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Your contact: +1 (317) 899-1395 • info@reo-usa.com

Series WKO-2C-B

Double core technology closed-loop current transformers for railway engineering

Series WKO-2C-B

Unique Selling Point


  • Fulfills the required railway engineering safety standards: EN 50178, EN 50155:2007 and IEC 61373:2010  
  • Shock- and vibration tested according to IEC 61373:2010
  • High current measurement accuracy of 0.5%
  • 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


The current transducer WKO-2C-B with hall effect elements and double-core  technology has an extended frequency response up to 120 kHz and an accurate phase response.  The WKO-2C-B guarantees an increased current measurement accuracy better than 0.5% in the whole frequency range: DC to 120 kHz.

A 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.

Modular design

The current transformer has a modular design which allows a variety of mounting options. The cost-effective basic model consists of a housing with screw terminals, bushing for cable and holes for fixing. Optionally, the transducers are available with mounting kit for busbars, molex connectors and feets for horizontal or vertical mounting.

According to: 

  • EN 50178:1997
  • UL 94-V0
  • EN 50178            
  • EN 50155:2007
  • IEC 61373:2010

Typical applications

  • Railway engineering

Technical Data


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

Mode of operation

Your contact: +1 (317) 899-1395 • info@reo-usa.com

Series WKO-2C-B

Double core technology closed-loop current transformers for railway engineering

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
Nominal current
m ISN [mA]

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

No-load
current
[mA]

WKO-2C-500

500

0 … ±1,000

±15…24

< ±0.5

5,000

100

72

36+IS

WKO-2C-1000

1,000

0 … ±1,500

±15…24

< ±0.5

5,000

200

38

24+IS

WKO-2C-2000

2,000

0 … ±3,000

±15…24

< ±0.5

5,000

400

27

78+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-500

< ±0.1

< 0.2

< 0.5

< 0.5

< 0.5

> 100

DC .. 120

WKO-2C-1000

< ±0.1

< 0.3

< 0.5

< 0.5

< 0.5

> 100

DC .. 120

WKO-2C-2000

< ±0.1

< 0.5

< 0.5

< 0.5

< 0.5

> 100

DC .. 120

 

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]

dI/dt
[A/µs]

Weight
[kg]

WKO-2C-500

10

9

600

6

12.5

> 100

0.240

WKO-2C-1000

15

12

600

6

14.5

> 100

0.450

WKO-2C-2000

25

21

600

6

14.5

> 100

1.620

Your contact: +1 (317) 899-1395 • info@reo-usa.com

Series WKO-2C-B

Double core technology closed-loop current transformers for railway engineering

Maximum measuring resistance 

Your contact: +1 (317) 899-1395 • info@reo-usa.com

Series WKO-2C-B

Double core technology closed-loop current transformers for railway engineering

Your contact: +1 (317) 899-1395 • info@reo-usa.com

Series WKO-2C-B

Double core technology closed-loop current transformers for railway engineering

Your contact: +1 (317) 899-1395 • info@reo-usa.com

Series WKO-2C-B

Double core technology closed-loop current transformers for railway engineering

Dimension drawing

 

Dimensions

Type

B [mm]

H [mm]

T [mm]

b1 [mm]

D [mm]

D1xD2 [mm]

  f [mm]

 e [mm]

WKO-2C-B-500

70

76

38

57

30.2

30.5x10.5

4.3

M5

WKO-2C-B-1000

94

100

42

78

38.5

40.5x13.5

5.3

M5

WKO-2C-B-2000

135

141

52

102

57.5

60.5x20.5

6.5

M5

Your contact: +1 (317) 899-1395 • info@reo-usa.com

Series WKO-2C-B

Double core technology closed-loop current transformers for railway engineering

Accessories

Your contact: +1 (317) 899-1395 • info@reo-usa.com

Series WKO-2C-B

Double core technology closed-loop current transformers for railway engineering

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, a 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 measurable 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 are 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.