109

Aluminium Housed

Wirewound Resistors

WH Series

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

Issue D · 03.06

Welwyn Components

Application Notes

Reference aluminium heatsink dimension

CECC 40203-006

L

W

H

Reference

cm

cm

cm

area sq. cm

AA (WH5)

15.5

10

5

410

BA (WH10)

CA (WH25)

18

13

5

544

DA (WH50)

Aluminium thickness 1mm

WH50 only

To load at maximum commercial rating (50W) mount on

heatsink 30.5cm x 30.5cm x 1.5mm.

Derating must be applied when resistors are mounted on a

heat sink of smaller dimensions than defined in Graph 1.

It is recommended that the resistor base should be coated

with heatsink compound before mounting to obtain the

stated operating characteristics.

The heatsink compound increases thermal conductivity to the

heatsink.

After soldering care should be taken to ensure that there are

no flux residues on the moulding compound, otherwise

insulation resistance will be reduced.

Packaging

Resistors are packed in plastic bags and boxed for maximum

protection.

Reference chassis

L

W

H

510

10

20

30

40

50

50 100

500 1000

AA

BA

CA

DA

RA

TE

D

DI

SS

IPAT

IO

N

AT

25

C

RA

TED

DIS

SIPAT

ION

AT 70

C

25C

25C

25C

70C

70C

70C

CECC 40 STYLE

Graph 1