Ohmite 250 Application Information
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
Application Notes
0.625"
15.875 mm
0.031"
0.794 mm
0.125"
3.175 mm
Diam.
0.063"
1.588 mm
Diam.
0.125"
3.175 mm
L
A
0.110":
2.776 mm
0.250"
6.350 mm
0.375"
9.525 mm
0.125"
3.175 mm
0.188"
4.763 mm
Diam.
0.109"
2.776 mm
Diam.
0.196"
4.979 mm
L
A
0.250"
6.350 mm
0.125"
3.175 mm
0.438"
11.113 mm
T
T
B
W
W
B
0.094"
2.381 mm
0.125"
3.175 mm
Diam.
0.063"
1.588 mm
Diam.
0.196"
4.979 mm
L
A
0.125"
3.175 mm
0.438"
11.113 mm
T
B
0.813"
20.638 mm
Core
size
Core
size
Core
size
0.125"
3.175 mm
0.188"
4.763 mm
Diam.
0.109"
2.776 mm
Diam.
0.196"
4.979 mm
L
A
0.125"
3.175 mm
0.438"
11.113 mm
(SS)
T
B
W
Core
size
0.188"
4.763 mm
0.250"
6.350 mm
0.531"
13.494 mm
(SSH)
0.125"
3.175 mm
0.188"
4.763 mm
Diam.
0.109"
2.776 mm
0.156" x0.313"
3.969 x 7.938 mm
Slot
L
A
0.5"
12.7 mm
T
B
W
Core
size
0.188"
4.763 mm
Brackets
cemented
in core
Core and Terminal Selection for Made to Order Type 250 Stackohm Resistors
Free Air
Wattage
Core Dimensions
Rating* Length L Width W Thickness T
†
Min.
Ohms
Practical
Ohms
Miniature
10 0.750” (19.050mm) 0.375” (9.525mm) 0.125” (3.175mm) 1 15,000 TA 1 1.000” (25.400mm) 0.375” (9.525mm) 51
15 1.000” (25.400mm) 0.375” (9.525mm) 0.125” (3.175mm) 1 25,000 TA 1 1.250” (31.750mm) 0.375” (9.525mm) 51
20 2.000” (50.800mm) 0.375” (9.525mm) 0.125” (3.175mm) 1 50,000 TA 1 2.313” (58.750mm) 0.375” (9.525mm) 51
12 0.688” (17.463mm) 0.594” (15.081mm) 0.234” (5.953mm) 1 20,000 TB ** 51
Intermediate
21 1.000” (25.400mm) 0.813” (20.638mm) 0.250” (6.350mm) 1 8,000 TD 2 1.313” (33.350mm) 0.594” (15.081mm) 51
25 1.500” (38.100mm) 0.813” (20.638mm) 0.250” (6.350mm) 1 15,000 TD 2 1.813” (46.050mm) 0.594” (15.081mm) 51
Standard
30 1.250” (31.750mm) 1.000” (25.400mm) 0.250” (6.350mm) 1 10,000 TE
3, 4 2.000” (50.800mm)
40 2.000” (50.800mm) 1.000” (25.400mm) 0.250” (6.350mm) 1 25,000 TE
3, 4 2.750” (69.850mm)
55 3.500” (88.900mm) 1.000” (25.400mm) 0.250” (6.350mm) 1 30,000 TE
3, 4 4.250” (107.950mm)
70 4.750” (120.650mm) 1.000” (25.400mm) 0.250” (6.350mm) 1 120,000‡ TE
3, 4 5.500” (139.700mm)
95 6.000” (152.400mm) 1.000” (25.400mm) 0.250” (6.350mm) 1 150,000‡ TE
3, 4 6.750” (171,450mm)
*Based on mounting on steeel panel 10” (254mm) x 10” x 0.040” (1.016mm).
†
Inside dimensions of core are: 0.250” (6.350mm) x 0.047” (1.191mm) for TA; 0.406”
(10.319mm) x 0.047” (1.191mm) for TB; 0.438” (11.113mm) x 0.063” (1.588mm) for TD;
0.672” (17.069mm) x 0.063” (1.588mm) for TE.
Code
Max.
for
Core
Dia.
Fig.
No. Dimension A Dimension B
5 1.750” (44.450mm)
5 2.500” (63.500mm)
5 4.000” (1.1.600mm)
5 5.250” (133.350mm)
5 6.500” (165.100mm)
‡
These sizes are Ohmicone (silicone-ceramic) coated–type 450-460.
**User supplies brackets.
Standard
Terminal
0.938” (23.813mm) 57
0.938” (23.813mm) 57
0.938” (23.813mm) 57
0.938” (23.813mm) 57
0.938” (23.813mm) 57
M O U N T I N G
In addition to the standard box bracket, stud type brackets are
available for stacking the standard size resistors. Stud type
brackets are available in two heights: standard (SS, 0.437”/
11.113mm) and high (SSH, 0.531”/13.494mm). The SSH stud
is recommended when stacking the adjustable Type 260, as it
assures clearance for the adjustable lugs to pass eachother.
Spacer washer No. 6027 (O.D. 0.219”/5.556mm, I.D. 0.125”/
3.175mm, thickness 0.094”/2.381mm) is recommended for use
with the miniature adjustable and fixed resistors to provide clearance, as explained above, or increased wattage. See chart.
Derating for stacked mounting
Stacked resistors should be derated to prevent excessive temperatures due to proximity. Approximate ratings are given in the
table.
No. of
Resistors
Percent of Single Unit Rating
Std. or Inter.
Miniature with
0.094” (2.381 mm)
Spacer WasherMiniature
2 70 70 75
3 60 60 69
4 50 50 60
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
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