Technical Specifications

For SR Surge Resistors with Surge Energy Rating 1.9 kJ - 10.4 kJ:

RESISTOR

TYPE

DIM.

CODE

OVERALL

DIMENSIONS

VOL.

MAX.

J

MAX.

W

T.T.C.

WT.

A/L

RESISTANCE RANGE

Do

Max

Lo

Max

Lp

Pitch

(v)

   

@25˚C

  

@25˚C

 

(t)

  

  

MIN

  

MAX

UNITS

 

(mm)

(mm)

(mm)

(cm3)

(J)

(W)

(s)

(g)

(cm)

(Ohms)

(Ohms)

SR 2250

2420

26

24

20 - 21

9.0

2250

5.75

390

22.5

2.3

4R7

2K2

SR 2825

2425

26

29

25 - 26

11.3

2825

6.50

435

28.0

1.8

5R6

2K7

SR 3500

2431

26

35

31 - 32

14.0

3500

7.50

465

34.0

1.5

6R8

3K3

SR 4175

2437

26

41

37 - 38

16.7

4175

8.50

490

40.0

1.2

10R0

4K7

SR 5200

2446

26

50

46 - 47

20.8

5200

10.00

520

50.0

1.0

10R0

4K7

SR 6975

3137

33

41

37 - 38

27.9

6975

11.50

605

66.0

2.0

5R6

2K7

SR 8675

3146

33

50

46 - 47

34.7

8675

13.25

655

81.5

1.6

6R8

3K3

SR 10375

3155

33

59

55 - 56

41.5

10375

15.25

680

97.0

1.4

8R2

3K9

NOTES

Vol (v) = Volume of Active Material (cm3)

T. T. C. = Thermal Time Constant (t)  (Seconds)


Maximum Working Voltages (V working)

The Maximum Working Voltage levels  can be derived from the appropriate formulae illustrated in the tables below. Examples are shown at the foot of this page.

Waveforms are defined in the usual manner: 1.2 / 50 µs indicates a rise time to peak value in 1.2 µs and an exponential decay to half amplitude in a total time of 50 µs.

SR 2250

 

IMPULSE / WAVESHAPE

MAX. WORKING VOLTAGE (kV)

(50 Hz rms)

1.9 x ( 2.3R / t ) 0.3

(1.2 / 50 µs)

1.26R x ( -1 + √ ( 1 + 26 / R ) )

(10 / 1000 µs)

0.0627R x ( -1 + √ ( 1 + 526 / R ) )

(500 / 5000 µs)

0.0126R x ( -1 + √ ( 1 + 2630 / R ) )


SR 2825

 

IMPULSE / WAVESHAPE

MAX. WORKING VOLTAGE (kV)

(50 Hz rms)

2.4 x ( 1.8R / t ) 0.3

(1.2 / 50 µs)

1.26R x ( -1 + √ ( 1 + 33 / R ) )

(10 / 1000 µs)

0.0627R x ( -1 + √ ( 1 + 658 / R ) )

(500 / 5000 µs)

0.0126R x ( -1 + √ ( 1 + 3288 / R ) )


SR 3500

 

IMPULSE / WAVESHAPE

MAX. WORKING VOLTAGE (kV)

(50 Hz rms)

2.9 x ( 1.5R / t ) 0.3

(1.2 / 50 µs)

1.18R x ( -1 + √ ( 1 + 41 / R ) )

(10 / 1000 µs)

0.0589R x ( -1 + √ ( 1 + 815 / R ) )

(500 / 5000 µs)

0.0118R x ( -1 + √ ( 1 + 4077 / R ) )


SR 4175

 

IMPULSE / WAVESHAPE

MAX. WORKING VOLTAGE (kV)

(50 Hz rms)

3.5 x ( 1.2R / t ) 0.3

(1.2 / 50 µs)

1.11R x ( -1 + √ ( 1 + 49 / R ) )

(10 / 1000 µs)

0.0552R x ( -1 + √ ( 1 + 973 / R ) )

(500 / 5000 µs)

0.0110R x ( -1 + √ ( 1 + 4866 / R ) )


SR 5200

 

IMPULSE / WAVESHAPE

MAX. WORKING VOLTAGE (kV)

(50 Hz rms)

4.4 x ( 1.0R / t ) 0.3

(1.2 / 50 µs)

1.00R x ( -1 + √ ( 1 + 61 / R ) )

(10 / 1000 µs)

0.0495R x ( -1 + √ ( 1 + 1210 / R ) )

(500 / 5000 µs)

0.0100R x ( -1 + √ ( 1 + 6050 / R ) )


SR 6975

 

IMPULSE / WAVESHAPE

MAX. WORKING VOLTAGE (kV)

(50 Hz rms)

3.5 x ( 2.0R / t ) 0.3

(1.2 / 50 µs)

1.84R x ( -1 + √ ( 1 + 29 / R ) )

(10 / 1000 µs)

0.0920R x ( -1 + √ ( 1 + 583 / R ) )

(500 / 5000 µs)

0.0184R x ( -1 + √ ( 1 + 2917 / R ) )


SR 8675

 

IMPULSE / WAVESHAPE

MAX. WORKING VOLTAGE (kV)

(50 Hz rms)

4.4 x ( 1.6R / t ) 0.3

(1.2 / 50 µs)

1.65R x ( -1 + √ ( 1 + 36 / R ) )

(10 / 1000 µs)

0.0826R x ( -1 + √ ( 1 + 725 / R ) )

(500 / 5000 µs)

0.0165R x ( -1 + √ ( 1 + 3626 / R ) )


SR 10375

 

IMPULSE / WAVESHAPE

MAX. WORKING VOLTAGE (kV)

(50 Hz rms)

5.2 x ( 1.4R / t ) 0.3

(1.2 / 50 µs)

1.46R x ( -1 + √ ( 1 + 43 / R ) )

(10 / 1000 µs)

0.0732R x ( -1 + √ ( 1 + 867 / R ) )

(500 / 5000 µs)

0.0146R x ( -1 + √ ( 1 + 4336 / R ) )


 

Worked example (50 Hz rms) :

Consider an SR 2825 Resistor with a Resistance Value of 100R0.

What is the maximum 50 Hz rms Working Voltage (kV) sustainable for an insertion time of 100 ms?

V working = 2.4 x (1.8R / t) 0.3 = 2.86 kV

(Note: R = Resistance Value in Ohms and t = 50 Hz Insertion time in ms)

 

Worked example (1.2 / 50 µs) :

Consider an SR 2825 Resistor with a Resistance Value of 100R0.

What is the maximum Working Voltage (kV) for a 1.2 / 50 µs waveform?

V working = 1.26R x (-1 + √(1 + 33 / R)) = 19.31 kV

 
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
                     
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