Aluminium housed wire-wound resistors series WD - Data sheet

Q: What is the intended mounting method for the WD series resistors?

The WD series is designed for direct heat sink attachment, enabling efficient heat transfer.

Q: What resistance and tolerance ranges are provided for the WD series?

Resistance values span from R01 to 150K. Tolerance is ±5% for values below 1 Ω, with tighter options and ±0.25% to ±5% for values above 1 Ω depending on the requested tolerance.

Q: Are electrical stability and temperature behavior specified for the WD resistors?

Yes. Temperature coefficients are listed (e.g., 60 ppm/°C for resistance values under 100 Ω and 30 ppm/°C for values above 100 Ω), along with insulation resistance and change-in-resistance limits under overload and shelf-life conditions.

Oct 12, 2026

Upload by MrHarris58

Aluminium housed wire-wound resistors series WD are high-quality, high-stability power resistors built for direct heat sink attachment, offering a wide resistance range from R01 to 150K and power ratings spanning 5 to 300 W. The series emphasizes excellent heat transfer with compact dimensions, good electrical stability, reliability, and mechanical rigidity, with an available non-inductive version. Electrical and mechanical specifications include tolerance options, temperature coefficient values, insulation resistance, overload and shelf-life changes, dielectric strength, and detailed standard heat-sink dimensions plus derating considerations.

LanguageEnglish

CategoryTechnology

FormatPDF

Pages2

Reading Time5 min

AccessFree to download

General description

Features

General series characteristics

Power derating

Electrical specifications

Mechanical specifications

Aluminium housed wire-wound resistors series WD Data sheet General description The WD style is a range of high quality, high stability Aluminium housed power resistors designed for direct heat sink attachment. A wide range of resistance values is available in 5 to 300 W. Design of higher wattage resistors for special applications can be done with ease. Features • Excellent heat transfers and small dimensions • Good electrical stability, reliability and mechanically very rigid • Non inductive version available • Values from R01 to 150K • Custom terminations, mounting arrangements possible • RoHS compliant General series characteristics | Characteristic | Condition | Compliance | | --- | --- | --- | | Tolerance | For values less than 1 Ω | ± 5% | | (Tighter tolerance available on request) | For values greater than 1 Ω | ± 0.25 to ± 5% | | Temperature co-efficient
(Lower TCR available on request) | For values less than 100 Ω For values greater than 100 Ω | 60 ppm / °C
30 ppm / °C | | Insulation resistance | Dry / Normal | 10GΩ min | | Change in resistance | | | | -short time overload | 10x rated voltage für 5 sec | ± 0.5% | | -shelf life | After 3 years | < ± 1% | | Incombustibility | 16x rated wattage for 5 sec | No flame | | Operating temperature | From-25°C to 250 °C | | Power derating Power Derating Chart % Rated Power 0 25 50 75 100 150 200 250 Temp (degC) WidapAG CH-3185 Schmitten Tel.: +41 26 497 50 60 Fax: +41 26 497 50 69 eMail: [info@widap.ch](info@widap.ch) Internet: [www.widap.ch](www.widap.ch) Edition 02.14 E 5-2-01 Aluminium housed wire-wound resistors series WD Data sheet Electrical specifications | Series | Power rating
on standard
heat sink
@ 25 °C | Power ra
ting with no
heat sink
@ 25°C | Resistance
range | Limiting
element
voltage
(DC / AC rms) | Dielectric
strength
(AC peak) | Weight
approx.
(g) | Standard heat sink | | | --- | --- | --- | --- | --- | --- | --- | --- | --- | | | | | | | | | Area
(cm2) | Thickness
(mm) | | WD5 | 10 | 5 | R01 - 10K | 160 | 1‘400 | 5 | 400 | 1 | | WD10 | 15 | 8 | R01 - 15K | 260 | 1‘400 | 7 | 400 | 1 | | WD25 | 25 | 12.5 | R01 - 35K | 550 | 2‘500 | 15 | 550 | 1 | | WD50 | 50 | 20 | R01 - 100K | 1‘250 | 2‘500 | 30 | 550 | 1 | | WD75 | 75 | 45 | R01 - 50K | 1‘400 | 5‘000 | 85 | 1‘000 | 3 | | WD100 | 100 | 50 | R01 - 100K | 1‘900 | 5‘000 | 115 | 1‘000 | 3 | | WD150 | 150 | 55 | R01 - 100K | 2‘500 | 5‘000 | 175 | 1‘000 | 3 | | WD200 | 200 | 50 | R01 - 50K | 1‘900 | 5‘000 | 475 | 3‘750 | 3 | | WD250 | 250 | 60 | R01 - 65K | 2‘200 | 5‘000 | 600 | 4‘800 | 3 | | WD300 | 300 | 75 | R01 - 80K | 2‘500 | 5‘000 | 700 | 5‘800 | 3 | Mechanical specifications | Series | L ± 0.5 | A max. | H | PX ± 0.3 | PX1 | PY ± 0.3 | M ± 0.5 | B max. | C max. | D | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | WD5 | 16.8 | 31 | 17 | 11.3 | - | 12.4 | 2.4 | 4.5 | 9 | 2.5 | | WD10 | 20.1 | 36.5 | 21 | 14.3 | - | 15.9 | 2.4 | 5.5 | 11 | 2.5 | | WD25 | 27.3 | 51.8 | 28 | 18.3 | - | 19.8 | 3.2 | 7.5 | 15 | 3 | | WD50 | 50.1 | 72.5 | 30 | 39.7 | - | 21.4 | 3.2 | 8.5 | 17 | 3 | | WD75 | 48.9 | 71 | 48 | 29 | - | 37.0 | 4.4 | 12 | 26 | 4 | | WD100 | 65.4 | 87.5 | 48 | 35 | - | 37.0 | 4.4 | 12 | 26 | 4 | | WD150 | 97 | 122 | 48 | 29 | 29 | 37.0 | 4.4 | 12 | 26 | 4 | | WD200 | 89 | 143 | 73 | 35 | - | 57.2 | 5.1 | 20.5 | 45 | 5.5 | | WD250 | 114 | 163 | 73 | 44.5 | - | 57.2 | 5.1 | 20.5 | 45 | 5.5 | | WD300 | 127 | 180 | 73 | 52 | - | 59.0 | 6.6 | 20.5 | 45 | 5.5 | WD5-50 WD75-150 WD200-300 WidapAG CH-3185 Schmitten Tel.: +41 26 497 50 60 Fax: +41 26 497 50 69 eMail: [info@widap.ch](info@widap.ch) Internet: [www.widap.ch](www.widap.ch) Edition 02.14 E 5-2-02

FAQs

What is the intended mounting method for the WD series resistors?

The WD series is designed for direct heat sink attachment, enabling efficient heat transfer.

What resistance and tolerance ranges are provided for the WD series?

Resistance values span from R01 to 150K. Tolerance is ±5% for values below 1 Ω, with tighter options and ±0.25% to ±5% for values above 1 Ω depending on the requested tolerance.

Are electrical stability and temperature behavior specified for the WD resistors?

Yes. Temperature coefficients are listed (e.g., 60 ppm/°C for resistance values under 100 Ω and 30 ppm/°C for values above 100 Ω), along with insulation resistance and change-in-resistance limits under overload and shelf-life conditions.

Oct 12, 2026

Upload by MrHarris58