FEATURES
• Flameproof and inorganic
• Higher power rating due to heat
sink capacity
• All welded construction
• Nonhygroscopic
• High surge construction
Metalohm Series
Wirewound Resistors
term. style 277
term. style 276 (sq. collar, G3923)
278 (oval collar, G3860)
0.250"
1.5" max.
term. style 279
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
ø0.195"
C
B
A
ø0.068"
±0.005
2
3
/
16
" max.
1.5" max.
term. style 252
0.5" D
ø0.089"
term. style 211
5
/
16
"
ø0.171"
1" max.
1.25" max.
0.75"
term. style 297
0.437" dia.
wire
term. style 298
wire
1.25" max.
Watts
Style
w/o heat sink w/ heat sink*
20/45M
20
45
40/70M
40
70
HV40-70M
40
70
50/100M
50
100
60/115M
60
115
Dimensions (inches)
A
B
C
1
1
7
/
16
1
7
/
8
2
9
/
16
3
3
7
/
16
2
9
/
16
3
3
7
/
16
3
11
/
16
4
1
/
8
4
9
/
16
9
/
16
5
6
6
7
/
16
D
3
/
4
3
/
4
7
/
8
3
/
4
3
/
4
Ohmic range**
0.05-6K
1.0-25K
1.0-25K
1.5-47.5K
2.5-81K
*Based on a 12”x12”x
1
/
8
” aluminum heat sink, using a thermal compound, in a 25°C ambient
**Standard winding ranges only listed, other values available; contact factory.
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
DIELECTRIC STRENGTH
Terminal Type 211
Style
20/45M
1500
40/70M
1500
HV40/70M
N/A
50/100M
1500
60/115M
1500
252, 279
N/A
1500
N/A
1500
1500
278
277
Dielectric Strength
N/A
N/A
N/A
2500
2500
N/A
N/A
N/A
4250
2500
2500
N/A
2500
2500
N/A
276
297
2500V
2500V
N/A
2500V
2500V
298
2500V
2500V
N/A
2500V
2500V
O R D E R I N G I N F O R M AT I O N
½½½½½½½½½½½½½½½½½½
Style
Non-inductive Tolerance Ohms
1R000 = 1.000
(optional)
K = 10%
10R5K = 10,500
J = 5%
H = 3%
G = 2%
F = 1%
Terminal Type
(see diagram)
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
27
DIY/Open Source Hardware
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