Technical Specifications

For SR Surge Resistors with Surge Energy Rating 250 J - 650 J:

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 0250

1111

13

15

11 - 12

1.0

250

1.50

165

3.5

0.9

12R0

5K6

SR 0325

1114

13

18

14 - 15

1.3

325

1.75

185

4.0

0.7

15R0

6K8

SR 0400

1117

13

21

17 - 18

1.6

400

2.00

200

5.0

0.6

18R0

8K2

SR 0550

1414

16

18

14 - 15

2.2

550

2.25

245

6.5

1.1

10R0

4K7

SR 0650

1417

16

21

17 - 18

2.6

650

2.50

260

7.0

0.9

12R0

5K6

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 0250

 

IMPULSE / WAVESHAPE

MAX. WORKING VOLTAGE (kV)

(50 Hz rms)

1.0 x ( 0.9R / t ) 0.3

(1.2 / 50 µs)

0.26R x ( -1 + √ ( 1 + 69 / R ) )

(10 / 1000 µs)

0.0131R x ( -1 + √ ( 1 + 1377 / R ) )

(500 / 5000 µs)

0.0026R x ( -1 + √ ( 1 + 6887 / R ) )


SR 0325

 

IMPULSE / WAVESHAPE

MAX. WORKING VOLTAGE (kV)

(50 Hz rms)

1.3 x ( 0.7R / t ) 0.3

(1.2 / 50 µs)

0.26R x ( -1 + √ ( 1 + 88 / R ) )

(10 / 1000 µs)

0.0131R x ( -1 + √ ( 1 + 1753 / R ) )

(500 / 5000 µs)

0.0026R x ( -1 + √ ( 1 + 8765 / R ) )


SR 0400

 

IMPULSE / WAVESHAPE

MAX. WORKING VOLTAGE (kV)

(50 Hz rms)

1.6 x ( 0.6R / t ) 0.3

(1.2 / 50 µs)

0.26R x ( -1 + √ ( 1 + 106 / R ) )

(10 / 1000 µs)

0.0131R x ( -1 + √ ( 1 + 2128 / R ) )

(500 / 5000 µs)

0.0026R x ( -1 + √ ( 1 + 10644 / R ) )


SR 0550

 

IMPULSE / WAVESHAPE

MAX. WORKING VOLTAGE (kV)

(50 Hz rms)

1.3 x ( 1.1R / t ) 0.3

(1.2 / 50 µs)

0.43R x ( -1 + √ ( 1 + 54 / R ) )

(10 / 1000 µs)

0.0214R x ( -1 + √ ( 1 + 1082 / R ) )

(500 / 5000 µs)

0.0043R x ( -1 + √ ( 1 + 5411 / R ) )


SR 0650

 

IMPULSE / WAVESHAPE

MAX. WORKING VOLTAGE (kV)

(50 Hz rms)

1.6 x ( 0.9R / t ) 0.3

(1.2 / 50 µs)

0.43R x ( -1 + √ ( 1 + 66 / R ) )

(10 / 1000 µs)

0.0214R x ( -1 + √ ( 1 + 1314 / R ) )

(500 / 5000 µs)

0.0043R x ( -1 + √ ( 1 + 6571 / R ) )


 

Worked example (50 Hz rms) :

Consider an SR 0650 Resistor with a Resistance Value of 1K0.

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

V working = 1.6 x (0.9R / t) 0.3 = 3.09 kV

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

 

Worked example (10 / 1000 µs) :

Consider an SR 0650 Resistor with a Resistance Value of 1K0.

What is the maximum Working Voltage (kV) for a 10 / 1000 µs waveform?

V working = 0.0214R x (-1 + √(1 + 1314 / R)) = 11.15 kV

 
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
                     
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