18 Ohmite Mfg. Co. 1600 Golf Rd., Suite 850, Rolling Meadows, IL 60008 • Tel. 1-866-9-OHMITE • Fax 1-847-574-7522 • www.ohmite.com • info@ohmite.com
The Ward Leonard brand,
HS/HSN Series, complements
Ohmite’s Military grade 89
Series as a lower cost alterna-
tive. The HS/HSN Series offers
the added feature of larger
sizes (100 and 250 watts) not
available in the 89 Series.
HS/HSN Series maintains
the same construction, materi-
als, and manufacturing tech-
niques as the Mil-R-18546
approved 89 Series. As a
made-to-order product, it is
recommended for higher vol-
ume applications.
FEATURES
• Standard winding (Model HS)
• Non-inductive winding (Model
HSN)
• Molded construction for total
environmental protection
• Complete welded construction
• Mounts on chassis to utilize
heat-sink effect
• High stability at conventional
power ratings
• Flat marking surface for easy
identification
HS/HSN Series
Aluminum Housed Axial Lead
Wirewound Resistors
Industrial/Commercial Grade
SPECIFICATIONS
Material
Housing: Aluminum with hard
anodic coating.
Internal Coating: Silicone.
Core: Ceramic.
Terminals: Solder-coated axial
lead.
Derating: Linearly from
100% @ +25°C to 0% @
+275°C.
Electrical
Tolerance: ±1% and ±5% (other
tolerances available).
Power rating: Rating is based on
chassis mounting area and tem-
perature stability. Proper heat
sink as follows: 25W units, 5" x
7" x 2" x .040" Aluminum chas-
sis; 50W units, 12" x 12" x .059"
Aluminum panel; 100 and 250W
units, 12” x 12” x .125 Aluminum
panel.
Maximum ohmic values:
See chart.
Overload: 5 times rated wattage
for 5 seconds.
Temperature coefficient:
Under 1Ω: ±90 ppm/°C
1 to 9.99Ω: ±50 ppm/°C
10Ωand over: ±30 ppm/°C.
Dielectric withstanding voltage:
25W, 1000VAC; 50W, 2000VAC;
100W and 250W, 4500VAC.
Power Rating Resistance Range Max. Working
Series (Watts) (Ohms) Voltage
HS25 25 .10 - 12.1K 550
HSN25 25 .005 - 6.04K 390
HS50 50 .10 - 39.2K 1250
HSN50 50 .005 - 19.6K 890
HS100 100 .05 - 29.4K 1900
HSN100 100 1.0 - 14.7K 1350
HS250 250 .10 - 35.7K 2300
HSN250 250 1.0 - 17.4K 1625
A
C
D
N
B FE
I
H
G
M
K
J
L
A
C
D
N
B FE
I
H
G
K
J
L
M
nickel-plated brass nut,
stainless steel stud
25 & 50 watt
100 & 250 watt
100
Percent Rated Watts
Ambient Temperature, °C
60
20
00 15050 275
80
40
25 100 200 25017575 125 225
25 watt
50, 100
& 250 watt
All types, mounted to
aluminum chassis
DERATING CURVE
DIMENSIONS
HS25 / HSN25 HS50 / HSN50 HS100 / HSN100 HS250 / HSN250
25 watt 50 watt 100 watt 250 watt
in. (mm) (upper figure) (upper figure) (lower figure) (lower figure)
Dim. A 0.719 ± .005 (18.26 ± .127) 1.562 ± .005 (39.67 ± .127) 2.75 ± .010 (69.85 ± .254) 3.875 ± .010 (98.425 ± .254)
Dim. B 0.781 ± .005 (19.84 ± .127) 0.844 ± .005 (21.44 ± .127) 2.25 ± .010 (57.15 ± .254) 2.5 ± .010 (63.50 ± .254)
Dim. C 1.062 ± .031 (26.97 ± .787) 1.968 ± .031 (49.99 ± .787) 3.50 ± .031 (88.90 ± .787) 4.5 ± .031 (114.30 ± .787)
Dim. D 1.938 ± .062 (49.23 ± 1.57) 2.781 ± .062 (70.64 ± 1.57) 5.478 ± .093 (139.14 ± 2.36) 7.0 ± .093 (117.80 ± 2.36)
Dim. E 0.550 ± .015 (13.97 ± .381) .630 ± .015 (16.00 ± .381) 1.812 ± .031 (46.02 ± .787) 2.125 ± .031 (53.98 ± .787)
Dim. F 1.080 ± .015 (27.43 ± .381) 1.140 ± .015 (28.96 ± .381) 2.812 ± .031 (71.42 ± .787) 3.0 ± .031 (76.20 ± .787)
Dim. G 0.546 ± .015 (13.87 ± .381) 0.610 ± .015 (15.49 ± .381) 1.75 ± .031 (44.45 ± .787) 2.188 ± .031 (55.58 ± .787)
Dim. H 0.075 ± .010 (1.90 ± .254) 0.088 ± .010 (2.24 ± .254) 1.88 ± .031 (4.78 ± .787) 0.250 ± .031 (6.35 ± .787)
Dim. I 0.231 ± .010 (5.87 ± .254) 0.260 ± .010 (6.60 ± .254) .770 ± .015 (19.56 ± .381) 0.955 ± .015 (24.26 ± .381)
Dim. J 0.172 ± .010 (4.37 ± .254) 0.196 ± .010 (4.98 ± .254) .375 ± .031 (9.52 ± .787) 0.312 ± .031 (7.92 ± .787)
Dim. K 0.125 ± .005 (3.18 ± .127) 0.125 ± .005 (3.18 ± .127) .188 ± .010 (4.78 ± .254) 0.188 ± .010 (4.78 ± .254)
Dim. L 0.115 ± .015 (2.92 ± .381) 0.107 ± .015 (2.72 ± .381) .219 ± .031 (5.56 ± .787) 0.25 ± .031 (6.35 ± .787)
Dim. M 0.085 ± .005 (2.16 ± .127) 0.085 ± .005 (2.16 ± .127) 12 - 24 UNC - 2A THD 1/4 - 20 UNC - 2A THD
Dim. N .438 ± .062 (11.13 ± 1.57) 0.438 ± .062 (11.13 ± 1.57) .989 ± .031 (25.12 ± .787) 1.25 ± .031 (31.75 ± .787)
