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
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
Metalohm Series
Wirewound Resistors
0.5"
A
B
C
ø0.195"
D
0.75"
term. style 276 (sq. collar, G3923)
278 (oval collar, G3860)
1.5" max.
0.250"
ø0.068"
±0.005
23/16" max.
term. style 277
1.5" max.
term. style 279
0.437" dia.
ø0.089"
1" max.
term. style 211
term. style 252
5/16"
1.25" max.
ø0.171"
term. style 297
1.25" max.
term. style 298
wire wire
FEATURES
• Flameproof and inorganic
• Higher power rating due to heat
sink capacity
• All welded construction
• Nonhygroscopic
• High surge construction
SPECIFICATIONS
Electrical
Wattage: Based on a 275°C “U”
characteristic derating curve
Temperature coefficient:
≥18 ohm: 0 ±90ppm/°C
8 < 18 ohm: 0 ±50ppm/°C
<8 ohm: 0 ±180ppm/°C
(TC for some watt/ohm combina-
tions may be lower)
Dielectric strength: Terminal to
case, depends on terminal style
(1500V min.)
Creepage: term. style 277: 1.2”
term. styles 278/276: 0.4”/0.7”
term. styles 211/252/279: 0.15”
Termination Wires
• Stranded, available in any insu-
lation rated 125°C or higher
(may require term. style 297).
• Custom cut/stripped lengths
• Can be potted or pre-soldered to
terminal styles 211 or 252
• Quick connect (fully or partially
insulated), ring or spade termina-
tions available
Dielectric Sleeves
• Steatite construction
• Style 276 meets UL/NEMA
2500V RMS for one minute
requirement
• Available as terminal styles 276,
277, 278, 297
Watts Dimensions (inches)
Style w/o heat sink w/ heat sink* A B C D Ohmic range**
20/45M 20 45 1 17/16 17/8 3/4 0.05-6K
40/70M 40 70 29/16 3 37/16 3/4 1.0-25K
HV40-70M 40 70 29/16 3 37/16 7/8 1.0-25K
50/100M 50 100 311/16 41/8 49/16 3/4 1.5-47.5K
60/115M 60 115 59/16 6 67/16 3/4 2.5-81K
*Based on a 12”x12”x1/8” aluminum heat sink, using a thermal compound, in a 25°C ambient
**Standard winding ranges only listed, other values available; contact factory.
DIELECTRIC STRENGTH
Terminal Type 211 252, 279 276 278 277 297 298
Style Dielectric Strength
20/45M 1500 N/A N/A N/A N/A 2500V 2500V
40/70M 1500 1500 2500 2500 N/A 2500V 2500V
HV40/70M N/A N/A N/A N/A 4250 N/A N/A
50/100M 1500 1500 2500 2500 N/A 2500V 2500V
60/115M 1500 1500 2500 2500 N/A 2500V 2500V
OPTIONS
• Noninductive versions (Aryton-
Perry windings)
• Terminal sleeves to increase
dielectric strength and maximize
creepage distance
• Variety of terminal choices
• Potted or soldered wire leads
including quick connect, ring,
spade terminals
• Tapped models ORDERING INFORMATION
Style
Ohms
1R000 = 1.000
10R5K = 10,500
Terminal Type
A = 211
B = 252
C = 279
D = 276
Non-inductive
(optional)
Tolerance
K = 10%
J = 5%
H = 3%
G= 2%
F = 1%
RoHS Compliant
E = 277
F = 278
G = 297
H = 298
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