Ohmite Mfg. Co.
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
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
Style
w/o heat sink
w/o heat sink
w/ heat sink*
w/ heat sink*
A
B
C
D
Ohmic range**
Ohmic range**
20/45M
20/45M
20
20
45
45
1
1
7
/
/
16
16
1
7
/
/
8
8
3
/
/
4
0.05-6K
0.05-6K
40/70M
40
70
2
9
/
16
3
3
7
/
16
3
/
4
1.0-25K
HV40-70M
HV40-70M
40
40
70
70
2
9
/
/
16
16
3
3
3
3
7
/
/
16
16
7
/
/
8
8
1.0-25K
1.0-25K
50/100M
50
100
3
11
/
16
4
1
/
8
4
9
/
16
3
/
4
1.5-47.5K
60/115M
60/115M
60
60
115
115
5
5
9
/
/
16
16
6
6
6
6
7
/
/
16
16
3
/
/
4
2.5-81K
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.
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 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
(see diagram)
Non-inductive
(optional)
Tolerance
K = 10%
J = 5%
H = 3%
G= 2%
F = 1%
