WELWYN SPF

General-Purpose Failsafe
Moulded Wirewound Resistors
Welwyn Components
SPH/SPF Series
• Drop-in replacement for BWH/BWF
• 2 watt rated with 1 watt dimensions
• ±5%, ±10% tolerance
• 0.1 ohm to 2400 ohms
• TCR’s as low as ±150 ppm/°C standard
(custom TC’s available)
•
Weldable and solderable leads
Electrical Data
Type
S PH
SPF
EIA RS-344 Style
CRU2
MIL-R-11 Style
RC32/RC42
Resistance
ohms
Tolerance
0R1 to 2k4
0R1 to 1k
%
Power rating
±5, ±10
watts
2 at 70°C
1 at 115°C
Derating to 0 at 160°C
Maximum continuous working voltage
√PR
Minimum insulation resistance
dry
10,000 Meg
wet
100 Meg
Minimum dielectric withstanding volts
ATM
1000V
Reduced pressure
RMS
625V
watts
145°C at 2 watts
Hotspot temperature rise
Current noise
Negligible
Physical Data
Dimensions (mm)
Type
L
D
d
f
SPH
14.3 ±0.25
5.72 ±0.20
0.813 ±0.05
38.1 ±3.2
SPF
14.3 ±0.25
5.72 ±0.20
0.813 ±0.05
38.1 ±3.2
d
D
L
f
Resistive Element
Encapsulation
All resistor types have resistance alloy winding on a braided
fibreglass substrate. Intermediate silicone coatings are used to
enhance processibility and to provide protection to the
resistive element.
The SPH and SPF are encapsulated utilizing a compression
moulded phenolic plastic material. The SPF has a flameresistance coating applied over the resistive element to provide
flammmability protection when destructive overloads may occur.
Termination
Marking
The SPH and SPF resistors are terminated using an alloy
coated copper flashed steel lead welded to a cap of the same
material. This termination assembly is mechanically crimped,
utilizing an improved crimp design, to the resistive element.
All products are marked utilizing heat and solvent resistant
colour code bands consistent with EIA/MIL requirements. The
first band is double width to designate wirewound construction.
A fifth band, blue in colour, is used for flameproof identification.
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.
© Welwyn Components Limited · Bedlington, Northumberland NE22 7AA, UK
Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: [email protected] · Website: www.welwyn-tt.com
A subsidiary of
TT electronics plc
Issue B · 03.02
93
General-Purpose Failsafe
Moulded Wirewound Resistors
Welwyn Components
SPH/SPF Series
Performance Data
SP H
Temperature coefficient (ppm)*
ohms
S PF
0.1 - 0.16 ±1000
0.10 ±1700
0.18 - 0.68 ±800
0.11 - 0.16 ±1000
0.75 -2400 ±400
0.18 - 0.68 ±800
0.75 - 1000 ±400
Dielectric withstanding voltage
RMS
1000V
Momentary overload
%
Low temperature operation
%
5
5
Temperature cycle
%
5
Humidity
%
5
Load life
%
5
Terminal strength
%
5
Resistance to solder heat
%
5
*All ppm levels listed are maximum
SPF Power Derating
Power (watts)
Power (watts)
SPH Power Derating
Ambient Temperature (°C)
Ambient Temperature (°C)
SPH & SFF Temperature Rise
Power (watts)
0.1 ohm
1 ohm
10 ohm
100 ohm
Temp (°C)
SPF Typical Fusing
1000 ohm
Time (seconds)
Power Input (watts)
Packaging
Resistors are supplied taped and reel. 4,000 pcs per reel.
© Welwyn Components Limited Bedlington, Northumberland NE22 7AA, UK
Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: [email protected] · Website: www.welwyn-tt.com
94
Issue B · 03.02