Compact Flameproof Power

Wirewound Resistors

WP-S Series

General Note

Welwyn Components reserves the right to make changes in product specification without notice or liability.

All information is subject to Welwyn’s own data and is considered accurate at time of going to print.

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

Issue E · 07.06

A subsidiary of

TT electronics plc

Welwyn Components

Dimensions (mm) & Weight (g)

Type

L max

D max

f min

d nom

PCB

Min

Wt.

mount

bend

nom

centres

radius

WP1S

6.2

2.8

21.20

0.6

10.20

0.6

0.22

WP2S

9.0

3.6

19.80

12.70

0.50

WP25S

12.5

4.5

17.80

18.40

0.50

WP3S

14.5

5.2

24.55

20.30

1.10

WP4S

13

5.6

22.75

18.90

1.00

WP5S

16.5

7.0

23.55

22.86

1.75

WP7S

25.0

8.8

28.30

31.40

4.40

A high purity ceramic substrate is assembled with interference fit end caps to which are welded the terminations. The resistive

element is wound on the substrate and welded to the caps. Flameproof silicone cement coating is applied prior to marking with

indelible ink. The components are then leadformed if required and packed.

Electrical Data

Physical Data

Construction

D

d

Lf

WP1S

WP2S

WP25S

WP3S

WP4S

WP5S

WP7S

Power rating at 25°C

watts

1

2

2.5

3

4

5

7

5s overload rating at 25ºC

watts

5

10

12.5

15

20

25

35

Short pulse performance

See Pulse Performance graphs

Resistance range

ohms

R068 to 430R

R05 to 900R

R05 to 900R

R01 to 2K2

R01 to 10K

R015 to 6K8 R15 to 10K

Limiting element voltage

volts

50

50

75

100

100

150

150

TCR

ppm/°C

<1R: 350

≥1R: 200

Isolation Voltage

volts

250

350

500

700

Resistance Tolerance

%

Standard Values

E24 preferred

Thermal Impedance

°C/watt

140

110

90

82

62

54

35

Ambient temperature range

°C

-55 to +155

<20R: 5

≥20R: 1, 2, 5

<20R: 5

≥20R: 1, 2, 5

<R10: 5

≥R10: 1, 2, 5

0.8

1.2