Welwyn Components

Telephone: +44 (0)1670 822181 · Facsimile: +44 (0)1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com

03. 09

UL Recognised Wirewound Resistors

ULW Series

Pulse Performance

Fusing Performance

1.2/50µsPeakVoltage Limit

(10 pulses at 10s intervals, R<5%)

Note the voltage show n is the nett voltage across the

resistor. The generator open circuit voltage w ill be higher

due to the generator's internal impedance.

0

1

2

3

4

5

0

10

20

30

40

50

60

70

80

90 100

Value (ohms)

Pulse Energy Limit

(single or low repetition rate, R<5%)

0

1

2

3

4

5

6

7

8

0

10 20

30

40

50 60

70

80 90 100

Value (ohms)

ULW2

ULW2

ULW3

ULW3

ULW4-10RJ has an energy limit of 4.3J and a 1.2/50 s peak voltage limit of 1.1kV.

ULW2 Fusing Characteristic

0

10

20

30

40

50

60

30

35

40

45

50

55

60

Initial Power (W)

Notes:

1. Typical fusing times are around 1/3 of the maximum figures.

2. After fusing the resistance value is >100 times the initial nominal value.

3. Suitable for fusing at voltages up to 264Vrms.

ULW3 & ULW4 Fusing Characteristic

0

10

20

30

40

50

60

50

60

70

80

90

100

110

120

Initial Power (W)