Resistors
Make Possible
Wirewound High
Surge Resistors
WHS Series
Enhanced surge & pulse energy capacity
UL94-V0 flameproof protection
Radial taped form available
Surface mount Z-form available
RoHS compliant with Pb-free terminations
Non inductive type available
All Pb-free parts comply with EU Directive 2011/65/EU (RoHS2)
Electrical Data
WHS2
Power rating at 25ºC
5s overload rating at 25ºC
Short pulse performance
Resistance range
TCR
Isolation Voltage
Resistance Tolerance
Standard Values
Thermal Impedance
Ambient temperature range
ºC/watt
ºC
110
82
ohms
ppm/ºC
volts
%
250
350
500
<20R: 5 ≥20R: 1, 2, 5
E12 preferred
54
-55 to +155
35
25
watts
watts
2
10
WHS3
3
15
1R0-330R
200
700
1000
5%
WHS5
5
25
WHS7
7
35
2R2-330R
WHS10
10
50
5R6-100R
WHS10N*
See Pulse Performance graphs
No Limiting Element Voltage applies to this series; the Rated Voltage is √(P.R).
*Non inductive (Ayrton Perry) winding
Physical Data
Dimensions (mm) & Weight (g)
Type
WHS2
WHS3
WHS5
WHS7
WHS10
WHS10N
L max
9.0
14.5
16.5
25.0
51.0
D max
3.6
5.2
7.0
8.8
10.5
11.0
f min
19.80
24.55
23.55
28.30
26.00
1.0
0.8
d nom
PCB
mount
centres
12.70
20.30
22.86
31.40
55.88
1.5
1.2
Min
bend
radius
Wt. nom
0.50
1.10
1.75
4.40
8.80
10.50
d
D
L
f
Construction
A high purity ceramic substrate is assembled with interference fit end caps to which are welded the terminations. The resistive
element is wound on the substrate and welded to the caps. Flameproof silicone cement coating is applied priorto marking with
indelible ink. The components are then leadformed if required and packed.
General Note
TT Electronics reserves the right to make changes in product specification without notice or liability.
All information is subject to TT Electronics’ own data and is considered accurate at time of going to print.
www.ttelectronicsresistors.com
© TT Electronics plc
07.14
Wirewound High Surge Resistors
Make Possible
WHS Series
Terminations
Material: Hot tin dipped copper wire
Strength:
The terminations meet the requirements of IEC 68.2.21
Solderability:
The terminations meet the requirements of IEC 115-1 Clause 4.17.3.2
Marking
WHS2, and WHS3 resistors are marked with four colour bands in conformance with IEC62.
The larger sizes are legend marked with type reference, resistance value and tolerance.
Solvent Resistance
The body protection and marking are resistant to all normal industrial cleaning solvents suitable for printed circuits.
Flammability
The resistor coating will not burn or emit incandescent particles under any condition of applied temperature or power overload.
Performance Data
Maximum
Load at rated power: 1000hrs @ 25°C
Dry heat: 1000hrs @ 200°C
Short term overload
Derating from rated power @25°C
Climatic
Climatic category
TRC & Vibration
Robustness & solder heat
Long term damp heat (56 days)
ΔR%
ΔR%
ΔR%
5 +0.001Ω
5 +0.001Ω
5 +0.001Ω
ΔR%
ΔR%
ΔR%
ΔR%
5 +0.001Ω
5 +0.001Ω
5 +0.001Ω
5 +0.001Ω
55/200/56
1
1
1
Typical
3
3
1
2
Zero at 280°C (See Thermal Performance graph).
Pulse Performance
Surge / Pulse Energy Capacity
(single or low repetition rate, ΔR < 5%)
1000
Energy (joules)
100
10
1
WHS10N
WHS10
WHS7
WHS5
WHS3
WHS2
1
10
Value (ohms)
100
1000
General Note
TT Electronics reserves the right to make changes in product specification without notice or liability.
All information is subject to TT Electronics’ own data and is considered accurate at time of going to print.
www.ttelectronicsresistors.com
© TT Electronics plc
07.14
Wirewound High Surge Resistors
Make Possible
WHS Series
WHS10N
WHS10
WHS7
WHS5
WHS3
WHS2
Thermal Performance
Derating Curve
Proportion of Rated Power (%)
Body Temperature Rise
WHS3
WHS5
WHS7
WHS10(N)
WHS10N
WHS2-7
Ambient Temperature °C
Temperature Rise (°C)
WHS2
Power (W)
Application Notes
1. If the resistors are to dissipate full rated power, it is recommended that the terminations should not be soldered closer than
4mm from the body.
2. Due to operating temperature limits imposed by some PCB materials, derating may be necessary. The surface temperature rise
at the centre of the body is shown under Thermal Performance.
3. WHS2, WHS3, WHS5 resistors can also be supplied with goalpost or lancet pre-formed leads. Radial form is available on
WHS2 and WHS3 only.
WHS2, WHS3, and WHS5 are also available in an SMD format with Z formed leads and packed in blister tape. See the Z-form
datasheet for details http://www.welwyn-tt.com/pdf/datasheet/Z-form.pdf
General Note
TT Electronics reserves the right to make changes in product specification without notice or liability.
All information is subject to TT Electronics’ own data and is considered accurate at time of going to print.
www.ttelectronicsresistors.com
© TT Electronics plc
07.14
Wirewound High Surge Resistors
Make Possible
WHS Series
Radial
Goalpost
Lancet
Z-form
Packaging
The standard packaging for WHS is taped. The critical dimensions are shown in Figure 1. The component wires will not protrude
beyond the outside edge of the tapes. Taped product is then packed into boxes or onto reels. See Ordering Procedure for details.
Alternative packaging is available by request. Pre-formed resistors are supplied loose packed in plastic bags or boxes.
Dimensions mm
WHS2
WHS3
WHS5
*WHS7
WHS10
WHS10N
b
52
67
63
85
9
9
b
52
67
63
85
105
105
c
5
10
10
10
10
20
Figure 1
c
f1
b
f2
-f2 < 1.4mm
*An offset lead length is available for WHS7
series. Consult factory for details
6
6
Ordering Procedure
Example: WHS2 at 100 ohms and 5% tolerance in ammo pack box of 2500 pieces -
WHS2 – 100R
Type
Value (use IEC62 code)
Tolerance (use IEC62 code)
F
G
J
Packing
A25
A1
T075
T07
A02
A01
Ammo
Tape
Ammo
WHS2
WHS3
WHS5
WHS7
WHS10
WHS10N
2500/box
1000/box
750/reel
700/reel
200/box
100/box
Standard
1%
2%
5%
J
A25
General Note
TT Electronics reserves the right to make changes in product specification without notice or liability.
All information is subject to TT Electronics’ own data and is considered accurate at time of going to print.
www.ttelectronicsresistors.com
© TT Electronics plc
07.14
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