www.vishay.com For technical questions, contact: sfer@vishay.com Document Number: 50017
61 Revision: 12-May-09
RWST
Vishay Sfernice
Fixed Wirewound High Power Vitreous Resistors
Electrical Traction Model
FEATURES
•95 W to 800 W at 25 °C
•NF C 93-214
•RB 25 x 168, RB 30 x 250
•Rugged construction for use in severe environmental
conditions
•Compliant to RoHS directive 2002/95/EC
The RWST vitreous wirewound high power resistors are known for their excellent reliability which has developed out of the
VISHAY SFERNICE experience over several decades in the field of high current applications.
Extremely severe conditions of use are encountered in electrical traction including repeated overloads. To withstand such
conditions the new RWST model is extremely rugged and is manufactured to a very carefully monitored process using the best
materials.
NF F 16101, 10/1988 and 16102, 04/1992: Not applicable (our parts are made of metallic and refractory materials).
NF C 93-214. Performances according to NF C 93-214.
DIMENSIONS in millimeters
“CS” Type 1 Collars
A
Ø B
26
D
E
F
Ø C
G
H15
J
STAINLESS STEEL 304 L COLLARS “CS” TYPE 1
A
23
3 Ø B
58
D
E
F
G
H 15
J
STAINLESS STEEL 304 L COLLARS “CS” TYPE 2
WELDED
S
TAINLE
SS
S
TEEL 304 L
CO
LLAR
S
“AN”
N
Ø C
Ø U
Ø B
A
L
Z
K V
P
WELDED STAINLESS STEEL 304 L BAND “B”
Q
S
Ø B
A
Ø C
R
T
Document Number: 50017 For technical questions, contact: sfer@vishay.com www.vishay.com
Revision: 12-May-09 62
RWST
Fixed Wirewound High Power Vitreous Resistors
Electrical Traction Model Vishay Sfernice
MECHANICAL SPECIFICATIONS
Mechanical Protection Vitreous enamel
Resistive Element Ni-Cr wire
Connections CS supporting collars
AN Collar or B on Request
Average Unit Weight 225 g to 2200 g
ENVIRONMENTAL SPECIFICATIONS
Temperature Limits - 55 °C + 450 °C
Climatic Category - 55 °C/+ 200 °C/56 days
DIMENSIONS in millimeters
RWST STYLE 25 x 13825 x 168 30 x 250 40 x 370 50 x 373
Connections AN-B
CS type 1
AN-B
CS type 1
AN-B
CS type 1
AN
CS type 2
AN
CS type 2
A ± 2 138 168 250 370 373
Ø B max. 28 28 33 45 53
Ø C min. 12 12 17 22 27.1
D 50 ± 1.5 50 ± 1.5 60 ± 1.5 69 max. 80 max.
E 27 ± 1 27 ± 1 30 ± 1 45 ± 1.5 51 ± 1.5
F ± 0.5 24 24 25 30 30
G - 4/+ 0 199 229 317 432 432
H - 4/+ 0 169 199 287 405 405
J ± 0.5 6.5 6.5 9 9 9
K 28.5 ± 1 28.5 ± 1 31 ± 1 45 ± 1.5 51 ± 1.5
L - 0/+ 0.5 9 9 13 18 18
N 117 ± 2 147 ± 2 227 ± 2 332 ± 3 332 ± 3
P 51 ± 1.5 51 ± 1.5 55 ± 1.5 81.5 max. 92.5 max.
Q - 0/+ 0.5 15 15 18 - -
R - 0.3/+ 0.9 26 26 31 - -
S max. 38.5 38.5 43.5 - -
T ± 1 23.5 23.5 26 - -
Ø U 5.7 5.7 5.7 9.2 9.2
V 33.5 ± 1 33.5 ± 1 36 ± 1 57 ± 1.5 63 ± 1.5
Z 6 6 5 10 11.5
Average unit
weight in g
(CS collars)
225 250 445 1400 2200
ELECTRICAL SPECIFICATIONS
Resistance Range 2.7 Ω to 430 kΩ
E12-E24 preferred series values)
Resistance Tolerance
Standard ± 5 %
Power Rating 95 W to 800 W at 25 °C
Temperature Coefficient 75 ppm/°C (typical)
Shelf Life 0.1 % year (typical)
PERFORMANCE
TESTS CONDITIONS REQUIREMENTS TYPICAL VALUES AND
DRIFTS
Short Time Overload 10 Pr during 5 s
Voltage limited at < 5000 V 2 % or 0.05 Ω 0.5 %
Climatic Sequence - 55 °C + 200 °C 2 % or 0.05 Ω
Insulation resistance 100 MΩ0.5 %
Humidity
(Steady State)
56 days
95 % relative humidity
3 % or 0.05 Ω
Insulation resistance 100 MΩ0.5 %
Thermal Shock Load at 100 % Pr followed by cold
temperature exposure at - 55 °C/15' 2 % or 0.05 Ω 0.5 %
Shock Severity 50 A
9 shocks/each side 1 % or 0.05 Ω 0.25 %
Vibration Severity 55B 1 % or 0.05 Ω 0.25 %
Terminal Strength AN
B
Traction 40 Ncm
Torque 60 Ncm 1 % or 0.05 Ω 0.5 %
Load Life 90'/30' cycle
1000 h at Pr 25 °C 5 % 1000 h 1 %
5000 h 2 %
www.vishay.com For technical questions, contact: sfer@vishay.com Document Number: 50017
63 Revision: 12-May-09
RWST
Vishay Sfernice Fixed Wirewound High Power Vitreous Resistors
Electrical Traction Model
NON INDUCTIVE WINDING
For high frequencies, low self induction resistors are available with special windings.
RWSTNI designation.
POWER RATING CHART
TEMPERATURE RISE
SPECIAL FEATURES
RWST STYLE 25 x 138 25 x 168 30 x 250 40 x 370 50 x 373
Designation NF C 93-214 - RB 25 x 168 RB 30 x 250 - -
Power Rating at 25 °C 95 W 160 W 280 W 500 W 700 W
Maximum Power
Rating at 25 °C P max. 110 W 180 W 320 W 600 W 800 W
Ohmic Range
(E12, E24 series) 2.7 Ω82 kΩ2.7 Ω100 kΩ4.7 Ω220 kΩ8.2 Ω360 kΩ12 Ω430 kΩ
Limiting Element Voltage 1400 V 1900 V 3000 V 4500 V 5000 V
Critical Resistance 18 kΩ20 kΩ30 kΩ36 kΩ30 kΩ
MODEL AND
STYLE
RWSTNI
25 x 138
RWSTNI
25 x 168
RWSTNI
30 x 250
RWSTNI
40 x 370
RWSTNI
50 x 373
OHMIC RANGE
(E12 SERIES)
22 Ω
2.5 kΩ
22 Ω
4 kΩ
120 Ω
6.8 kΩ
120 Ω
8.2 kΩ
150 Ω
8.2 kΩ
AMBIENT TEMPERATURE IN °C
% RATED POWER
100
75
50
25
0
0 65 130 195 260 325 390 455
RATED POWER IN W
HOT SPOT TEMPERATURE IN °C
400
300
200
100
0
10 100 1000
RWST 25 × 138
RWST 25 × 168
RWST 30 × 250
RWST 40 × 370
RWST 50 × 373
Document Number: 50017 For technical questions, contact: sfer@vishay.com www.vishay.com
Revision: 12-May-09 64
RWST
Fixed Wirewound High Power Vitreous Resistors
Electrical Traction Model Vishay Sfernice
PACKAGING
Box: Fixed quantity depending on size and connections.
MARKING
SFERNICE trademark, model, style, nominal resistance
(in Ω), tolerance (in %), manufacturing date.
ORDERING INFORMATION
RWST 25 × 138B 56U ± 5 %B06 e
MODEL STYLE NON-INDUCTIVE
WINDING
Optional
SPECIAL
DESIGN
Optional
CONNECTIONS OHMIC VALUE
Custom items are
subject to extra-charge
and min. order.
Please see price list.
TOLERANCE PACKAGING LEAD
(Pb)-FREE
GLOBAL PART NUMBER INFORMATION
GLOBAL
MODEL SIZE LEADS OPTION OHMIC VALUE TOLERANCE PACKAGING SPECIAL
RWST 25138
25168
30250
40370
50373
A = AN
B = B
C = CS
F = Faston
N = Non
inductive
winding
The first three digits are
significant figures and
the last digit specifies
the number of zeros to
follow. R designates
decimal point.
4700 = 470 Ω
48R8 = 48.7 Ω
R010 = 0.01 Ω
R470 = 0.47 Ω
J = 5.0 %
K = 10 %
Box:
BO1
BO2
BO2NA
BO4
BO4NA
BO6
BO6NA
As applicable.
Example: BA7
256C40JW SR T 1 870B0 4
Document Number: 91000 www.vishay.com
Revision: 18-Jul-08 1
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Legal Disclaimer Notice
Vishay
All product specifications and data are subject to change without notice.
Vishay Intertechnology, Inc., its affiliates, agents, and employees, and all persons acting on its or their behalf
(collectively, “Vishay”), disclaim any and all liability for any errors, inaccuracies or incompleteness contained herein
or in any other disclosure relating to any product.
Vishay disclaims any and all liability arising out of the use or application of any product described herein or of any
information provided herein to the maximum extent permitted by law. The product specifications do not expand or
otherwise modify Vishay’s terms and conditions of purchase, including but not limited to the warranty expressed
therein, which apply to these products.
No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted by this
document or by any conduct of Vishay.
The products shown herein are not designed for use in medical, life-saving, or life-sustaining applications unless
otherwise expressly indicated. Customers using or selling Vishay products not expressly indicated for use in such
applications do so entirely at their own risk and agree to fully indemnify Vishay for any damages arising or resulting
from such use or sale. Please contact authorized Vishay personnel to obtain written terms and conditions regarding
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