Cement Coated
Wirewound Resistors
W30 Series
Welwyn Components
•
Values down to 10m ohms
•
Tolerance to 1%
•
Flameproof protection
•
Custom built to meet pulse requirements
Electrical Data
W31
Power rating at 25°C
Power rating at 70°C
Resistance range
TCR (-55 to 155°C)
Resistance tolerance
Standard values
Thermal impedance
Ambient temperature range
Limiting element voltage
TCR
°C/watt
°C
volts
ppm/°C
watts
watts
ohms
ppm/°C
%
3.0
2.5
0R01 to 10K
See below
5 2 1
E24 series preferred
83
-55 to 155
100
0.01 ohms <1000
0.033 ohms <500
0.091 ohms <200
10 ohms <150
10K ohms <100
Other values to special order
Notes
Physical Data
Maximum Dimensions (mm) and Weight (g)
Type
W31
L max.
13
D max.
5.6
f min.
22.75
d nom.
0.8
Wt.nom.
1.0
d
D
L
f
Construction
A high quality ceramic substrate is assembled with
interference fit end caps to which are welded the element
winding and termination wires. The protection is then applied
to the body, providing an effective seal which is impervious to
moisture, shock, vibration, fungus and salt spray.
Marking
W31 resistors are legend marked with type reference,
resistance value and tolerance. Values are marked in
accordance with IEC 62.
Solvent Resistance
The body and marking are resistant to all normal industrial
cleaning solvents suitable for printed circuits.
Terminations
Material
Strength
Solderability
Solder coated copper.
The terminations meet the requirements of
IEC 68.2.21.
The terminations meet the requirements of
IEC 115-1, Clause 4.17.3.2.
Flammability
The resistor coating will not burn under any condition of
applied temperature or component overload.
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.
A subsidiary of
TT electronics plc
Issue D · 07.06
© Welwyn Components Limited
· Bedlington, Northumberland NE22 7AA, UK
Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
99
WELWYN [ WELWYN COMPONENTS LIMITED ]
