Aluminium Housed
Wirewound Resistors
WH Series
High power dissipation up to 300W
All welded construction
Suitable for severe environments
Designed for excellent thermal conductivity to heatsink
RoHS compliant
Electrical Data
WH5 WH10 WH25 WH50 Notes
Power rating at 25C watts 10 15 25 50 * On standard heatsink
Resistance range ohms 0R01 to 10K 0R01 to 20K 0R01 to 44K 0R015 to 120K
TCR (-55 to 200C) ppm/C <10R: 75 10R to <100R: 50 100R: 25
Resistance tolerance % 1(F), 2(G), 5(J) and 10(K)
Low value limits ohms 1R at 1% 0R5 at 2% 0R05 at 5% 0R01 at 10% WH50 0R015 at 10%
Isolation voltage volts 1500 1500 3000 3000 DC or AC peak
* For load at maximum rating mount on aluminium heatsink 30.5 cm x 30.5 cm x 1.5 mm
CECC 40203-006 Requirements * AA BA CA DA Notes
Power rating at 25C watts 10 15 25 40 On standard heatsink
Resistance range ohms 0R05 to 3K4 0R05 to 15K 0R05 to 33K 0R05 to 82K
TCR (-55 to 200C) ppm/C 5R to 10R: 100 >10R: 50
Resistance tolerance % 1(F), 2(G), and 5(J)
Low value limits ohms 1R at 1% 0R5 at 2% 0R05 at 5%
Isolation voltage volts 1000 1000 2000 2000 DC or AC peak
* This table indicates the CECC specification requirements which are met or exceeded by the corresponding WH series products.
Limiting element voltage volts 150 250 500 1250 DC or AC rms
Standard values E24 preferred range Other values to order
Thermal impedance C/watt 16.0 10.0 6.0 3.5 On standard heatsink
Ambient temperature range C -55 to 200
WH100 WH200 WH300 Notes
Power rating at 25C watts 100 200 300 On standard heatsink
Resistance range ohms 0R01 to 70K 0R01 to 50K 0R01 to 68K
TCR (-55 to 200C) ppm/C 1K0: 100 >1K0: 25
Resistance tolerance % Standard 5(J) and 10(K). also available : 1(F) and 2(G)
Low value limits ohms Typically 0R05: 5% 0R047: 10%
Isolation voltage volts 6360 7070 7070 DC or AC peak
Limiting element voltage volts 1900 1900 2500 DC or AC rms
Standard values E24 preferred range Other values to order
Thermal impedance C/watt 1 0.7 0.6 On standard heatsink
Ambient temperature range C -55 to 200
General Note
Welwyn Components reserves the right to make changes in product specification without notice or liability.
All information is subject to Welwyns own test data and is considered accurate at time of print.
Welwyn Components Limited
Welwyn Electronics Park, Bedlington, Northumberland, NE22 7AA, England. Tel: 01670 822181 Fax: 01670 829465 Web: www.welwyn-tt.com
Aluminium Housed
Wirewound Resistors
Physical Data
Dimensions (mm) & Weight (g)
WH5 - 50
A B C E F G H L M N Dt Wt.
Type
Max 0.3 0.3 Min Max Max Dia 0.2 Max 0.5 Max Min Nom
WH5 30 12.4 11.3 1.9 17 9 2.4 17.0 4.3 1.8 2.5 3.6
WH10 36.5 15.9 14.3 1.9 21 11 2.4 21.0 5.2 2.2 2.9 5.6
WH25 51 19.8 18.3 2.8 28 15 3.3 29.0 7.2 2.6 4.3 13
WH50 72.5 21.4 39.7 2.8 30 16 3.3 51.0 7.9 2.6 5.1 29
WH100 300
A B C D E F G H J K L M Dt Wt.
Max Max Max Max Max 0.3 0.3 Max Max Max Nom* Max Min Nom
47.5 88 24.1 27.3 65.2 35 37 11.8 15.4 3.7 4.4 - 7.0 115
WH100
72.5 145.7 41.8 45.5 89.7 70 57.2 20.5 10.4 5.5 5.1 103.4 15 475
WH200
72.5 184.4 41.8 45.5 127.7 104 59 20.5 12.4 5.5 6.6 141.4 15 700
WH300
* WH100: 0.25, WH200 & WH300: 0.45
WH100 WH200 & 300
WH5 - 50
End face tracking distance = Dt
Construction
Marking
Cap and lead assemblies are fitted to a high purity
The resistors are legend marked with type reference,
ceramic substrate. The resistive element is wound onto
resistance value and tolerance which will withstand all
the substrate and welded to the caps. The wound rod is
accepted industrial cleaning fluids. Values are marked
then moulded and fitted into aluminium housing to give
in accordance with IEC 62
optimum stability and reliability.
General Note
Welwyn Components reserves the right to make changes in product specification without notice or liability.
All information is subject to Welwyns own test data and is considered accurate at time of print.
Welwyn Components Limited
Welwyn Electronics Park, Bedlington, Northumberland, NE22 7AA, England. Tel: 01670 822181 Fax: 01670 829465 Web: www.welwyn-tt.com