Interactive dimension reference
NEMA Motor Frame Dimensions Lookup
Select a frame to see where the principal mounting and shaft dimensions are measured.
Default: 145T. The drawing is schematic—not a scaled manufacturer outline—and is intended to locate D, E, 2F, H, U, and BA.
- Frame
- 145T
- D · shaft center height
- 3-1/2 in
- E · transverse mounting
- 2-3/4 in
- 2F · longitudinal hole spacing
- 5 in
- H · mounting hole / slot
- 11/32 in
- U · shaft diameter
- 7/8 in
- V · shaft reference
- 2-1/4 in
- BA · shaft / mounting reference
- 2-1/4 in
Reverse lookup from field measurements
Enter shaft center height D, shaft diameter U, or both. Exact values are preferred; the closest-reference check is limited to ±1/8 in for D and ±1/16 in for U (metric equivalents).
Enter one or both measurements to narrow possible frame references.
Replacement warning: matching a NEMA frame does not prove a drop-in replacement. Verify the exact motor outline drawing, mounting configuration, shaft extension, conduit-box location, enclosure, electrical ratings, bearings, and required clearances before purchase or installation.
Server-rendered reference
NEMA Electric Motor Frame Dimensions
A transformed dimensional reference for common current T/TS frames plus a limited legacy context set.
Search a designation such as 184T, filter by frame family, or sort D/U. The selected unit control above converts the visible dimensional values from their canonical inch basis.
No supported frame matches these filters. Clear the search or change the frame family; one or two measurements alone may not uniquely identify a motor frame.
Scroll horizontally to view additional columns and vertically to view additional frames. Column headers remain visible while scrolling.
| Family | Mounting dimensions (in) | Shaft dimensions (in) | Notes / status | Copy | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| E | 2F | H | V | BA | ||||||
| 56 | Fractional | 3-1/2 | 2-7/16 | 3 | 11/32 | 5/8 | 1-7/8 | 2-3/4 | Fractional-horsepower NEMA reference. | |
| 143T | T / TS | 3-1/2 | 2-3/4 | 4 | 11/32 | 7/8 | 2-1/4 | 2-1/4 | Current T-frame family. | |
| 145T | T / TS | 3-1/2 | 2-3/4 | 5 | 11/32 | 7/8 | 2-1/4 | 2-1/4 | Current T-frame family. | |
| 182T | T / TS | 4-1/2 | 3-3/4 | 4-1/2 | 13/32 | 1-1/8 | 2-3/4 | 2-3/4 | Current T-frame family. | |
| 184T | T / TS | 4-1/2 | 3-3/4 | 5-1/2 | 13/32 | 1-1/8 | 2-3/4 | 2-3/4 | Current T-frame family. | |
| 213T | T / TS | 5-1/4 | 4-1/4 | 5-1/2 | 13/32 | 1-3/8 | 3-3/8 | 3-1/8 | Current T-frame family. | |
| 215T | T / TS | 5-1/4 | 4-1/4 | 7 | 13/32 | 1-3/8 | 3-3/8 | 3-1/8 | Current T-frame family. | |
| 254T | T / TS | 6-1/4 | 5 | 8-1/4 | 17/32 | 1-5/8 | 4 | 3-3/4 | Current T-frame family. | |
| 256T | T / TS | 6-1/4 | 5 | 10 | 17/32 | 1-5/8 | 4 | 3-3/4 | Current T-frame family. | |
| 284T | T / TS | 7 | 5-1/2 | 9-1/2 | 17/32 | 1-7/8 | 4-5/8 | 4-3/8 | Current T-frame family. | |
| 286T | T / TS | 7 | 5-1/2 | 11 | 17/32 | 1-7/8 | 4-5/8 | 4-3/8 | Current T-frame family. | |
| 284TS | T / TS | 7 | 5-1/2 | 9-1/2 | 17/32 | 1-5/8 | 3-1/4 | 3 | Short-shaft TS variant. | |
| 286TS | T / TS | 7 | 5-1/2 | 11 | 17/32 | 1-5/8 | 3-1/4 | 3 | Short-shaft TS variant. | |
| 324T | T / TS | 8 | 6-1/4 | 10-1/2 | 21/32 | 2-1/8 | 5-1/4 | 5 | Current T-frame family. | |
| 326T | T / TS | 8 | 6-1/4 | 12 | 21/32 | 2-1/8 | 5-1/4 | 5 | Current T-frame family. | |
| 324TS | T / TS | 8 | 6-1/4 | 10-1/2 | 21/32 | 1-7/8 | 3-3/4 | 3-1/2 | Short-shaft TS variant. | |
| 326TS | T / TS | 8 | 6-1/4 | 12 | 21/32 | 1-7/8 | 3-3/4 | 3-1/2 | Short-shaft TS variant. | |
| 364T | T / TS | 9 | 7 | 11-1/4 | 21/32 | 2-3/8 | 5-7/8 | 5-5/8 | Current T-frame family. | |
| 365T | T / TS | 9 | 7 | 12-1/4 | 21/32 | 2-3/8 | 5-7/8 | 5-5/8 | Current T-frame family. | |
| 364TS | T / TS | 9 | 7 | 11-1/4 | 21/32 | 1-7/8 | 3-3/4 | 3-1/2 | Short-shaft TS variant. | |
| 365TS | T / TS | 9 | 7 | 12-1/4 | 21/32 | 1-7/8 | 3-3/4 | 3-1/2 | Short-shaft TS variant. | |
| 404T | T / TS | 10 | 8 | 12-1/4 | 13/16 | 2-7/8 | 7-1/4 | 7 | Current T-frame family. | |
| 405T | T / TS | 10 | 8 | 13-3/4 | 13/16 | 2-7/8 | 7-1/4 | 7 | Current T-frame family. | |
| 404TS | T / TS | 10 | 8 | 12-1/4 | 13/16 | 2-1/8 | 4-1/4 | 4 | Short-shaft TS variant. | |
| 405TS | T / TS | 10 | 8 | 13-3/4 | 13/16 | 2-1/8 | 4-1/4 | 4 | Short-shaft TS variant. | |
| 444T | T / TS | 11 | 9 | 14-1/2 | 13/16 | 3-3/8 | 8-3/8 | 8-1/4 | Current T-frame family. | |
| 445T | T / TS | 11 | 9 | 16-1/2 | 13/16 | 3-3/8 | 8-3/8 | 8-1/4 | Current T-frame family. | |
| 447T | T / TS | 11 | 9 | 20 | 13/16 | 3-3/8 | 8-3/8 | 8-1/4 | Large T-frame family; verify the catalog drawing. | |
| 449T | T / TS | 11 | 9 | 25 | 13/16 | 3-3/8 | 8-1/2 | 8-1/4 | Large T-frame family; verify the catalog drawing. | |
| 444TS | T / TS | 11 | 9 | 14-1/2 | 13/16 | 2-3/8 | 4-5/8 | 4-1/2 | Short-shaft TS variant. | |
| 445TS | T / TS | 11 | 9 | 16-1/2 | 13/16 | 2-3/8 | 4-5/8 | 4-1/2 | Short-shaft TS variant. | |
| 447TS | T / TS | 11 | 9 | 20 | 13/16 | 2-3/8 | 4-5/8 | 4-1/2 | Short-shaft TS variant; verify the catalog drawing. | |
| 449TS | T / TS | 11 | 9 | 25 | 13/16 | 2-3/8 | 4-3/4 | 4-1/2 | Short-shaft TS variant; verify the catalog drawing. | |
| 254U | U (legacy) | 6-1/4 | 5 | 8-1/4 | 17/32 | 1-3/8 | 3-3/4 | 4-1/4 | Legacy U-frame reference. | |
| 256U | U (legacy) | 6-1/4 | 5 | 10 | 17/32 | 1-3/8 | 3-3/4 | 4-1/4 | Legacy U-frame reference. | |
| 284U | U (legacy) | 7 | 5-1/2 | 9-1/2 | 17/32 | 1-5/8 | 4-7/8 | 4-5/8 | Legacy U-frame reference. | |
| 286U | U (legacy) | 7 | 5-1/2 | 11 | 17/32 | 1-5/8 | 4-7/8 | 4-5/8 | Legacy U-frame reference. | |
| 324U | U (legacy) | 8 | 6-1/4 | 10-1/2 | 21/32 | 1-7/8 | 5-5/8 | 5-3/8 | Legacy U-frame reference. | |
| 326U | U (legacy) | 8 | 6-1/4 | 12 | 21/32 | 1-7/8 | 5-5/8 | 5-3/8 | Legacy U-frame reference. | |
| 203 | Pre-1953 | 5 | 4 | — | — | 3/4 | 2 | 3-1/8 | Pre-1953 frame; older source table uses F/N nomenclature. | |
| 204 | Pre-1953 | 5 | 4 | — | — | 3/4 | 2 | 3-1/8 | Pre-1953 frame; older source table uses F/N nomenclature. | |
| 224 | Pre-1953 | 5-1/2 | 4-1/2 | — | — | 1 | 3 | 3-1/2 | Pre-1953 frame; older source table uses F/N nomenclature. | |
| 225 | Pre-1953 | 5-1/2 | 4-1/2 | — | — | 1 | 3 | 3-1/2 | Pre-1953 frame; older source table uses F/N nomenclature. | |
| 254 | Pre-1953 | 6-1/4 | 5 | — | — | 1-1/8 | 3-3/8 | 4-1/4 | Pre-1953 frame; older source table uses F/N nomenclature. | |
| 284 | Pre-1953 | 7 | 5-1/2 | — | — | 1-1/4 | 3-3/4 | 4-3/4 | Pre-1953 frame; older source table uses F/N nomenclature. | |
| 324 | Pre-1953 | 8 | 6-1/4 | — | — | 1-5/8 | 4-7/8 | 5-1/4 | Pre-1953 frame; older source table uses F/N nomenclature. | |
| 326 | Pre-1953 | 8 | 6-1/4 | — | — | 1-5/8 | 4-7/8 | 5-1/4 | Pre-1953 frame; older source table uses F/N nomenclature. | |
The reference focuses on the dimensions most useful for identification and mounting checks. ABB notes that its quick-reference chart contains typical legacy Baldor-Reliance dimensions and that exact dimensional data should be checked against the specific catalog-number drawing. Pre-1953 rows use older dimensional nomenclature, so 2F and H are intentionally left blank where the modern fields are not asserted by the source table.
Table actions
Full-table CSV export is intentionally disabled because the controlling standards and manufacturer reference compilations are copyright-protected.
How to Read a Motor Frame Number
A NEMA frame designation is primarily a dimensional reference. It helps define mounting and shaft geometry, but it does not by itself specify horsepower, speed, voltage, enclosure, efficiency, insulation system, bearings, or overall motor length.
- 145T
- A current T-frame designation. Use the chart to check mounting and shaft dimensions, then verify the actual motor drawing.
- 286TS
- A TS short-shaft variant. Do not substitute a 286T shaft arrangement without checking U, V, BA, and the driven equipment interface.
- 284U
- A legacy U-frame reference. Treat it as a different dimensional generation rather than assuming equivalence with a 284T.
What D, E, 2F, H, U, V, and BA mean
- D
- Shaft centerline height above the mounting surface. This is one of the fastest field checks for a foot-mounted replacement.
- E
- Transverse mounting reference associated with the foot-hole pattern.
- 2F
- Longitudinal mounting-hole spacing used to compare the motor base footprint.
- H
- Mounting hole or slot dimension shown by the reference table.
- U
- Shaft diameter. This must agree with the coupling, sheave, sprocket, or other driven-component bore.
- V
- Shaft reference dimension used with the shaft geometry shown in the standards/manufacturer reference.
- BA
- Shaft-to-mounting reference dimension used when checking where the shaft shoulder and driven equipment land relative to the base.
How to Match a Replacement Motor Frame
Start with the complete nameplate frame designation when it is readable. If it is missing, use field measurements only to narrow candidates, then verify the motor-specific outline drawing before ordering.
- Record the entire designation. A suffix such as T, TS, TC, or another mounting code can change the physical interface.
- Measure shaft center height D and shaft diameter U. These quickly eliminate many incorrect frames.
- Check E, 2F, and H at the base. Confirm that the actual bolt pattern matches the foundation or machine.
- Check shaft extension geometry. Compare U, V, BA, key/keyseat, coupling engagement, and any driven-equipment clearance.
- Verify mounting style and complete outline. C-face/D-flange details, conduit-box position, overall length, bearings, and accessories can vary.
- Verify electrical duty separately. Match voltage, phase, frequency, horsepower, speed, service factor, enclosure, efficiency, and application requirements.
Sanity check: identical horsepower does not guarantee identical frame geometry, and identical basic frame geometry does not guarantee the complete motors are application-equivalent.
T Frames, U Frames, TS Frames, and Older NEMA Frames
The suffix is part of the dimensional identification. WEG’s published frame-assignment reference separates the current T-frame program, the 1952 U-frame program, and original NEMA frames; ABB likewise presents T, U, TS, and pre-1953 references separately.
T frame
Use the current T-frame row when the nameplate explicitly carries the T suffix. Pair the frame lookup with the motor’s actual outline drawing.
TS frame
TS is a short-shaft variant in applicable frame families. The mounting footprint may be related to the T family while the shaft dimensions differ materially.
U frame
U frames belong to an older dimensional program. Do not replace a U frame by matching only the numeric stem to a T frame.
Pre-1953 frame
Older frames use different nomenclature in the historical reference table. This page leaves modern-only fields blank rather than forcing incompatible labels.
NEMA vs IEC Motor Frame Sizes
NEMA and IEC frame systems are separate dimensional standards. IEC 60072-1:2022 covers dimensional series for rotating electrical machines and includes foot-mounted shaft heights from 56 mm through 400 mm in its stated scope. An IEC frame number must not be looked up in this NEMA table as though the numbers were interchangeable.
Practical rule: when converting between a NEMA and IEC motor, compare the complete shaft, mounting, flange, and envelope drawing. Do not use a numeric frame-number similarity as a conversion.
Worked Motor Frame Examples
Example 1: checking a 184T replacement
Assumption: the existing nameplate reads 184T and the replacement is also foot mounted.
The reference gives D = 4-1/2 in, E = 3-3/4 in, 2F = 5-1/2 in, U = 1-1/8 in, V = 2-3/4 in, and BA = 2-3/4 in for the transformed fields used here. In metric, D is 114.3 mm and U is 28.6 mm.
Interpretation: those dimensions are a strong mounting/shaft compatibility check, but the final decision still requires the specific motor drawing, mounting style, shaft extension details, and electrical ratings.
Example 2: nameplate missing
Assumption: field measurements are D ≈ 3.50 in and U ≈ 0.875 in.
Those measurements are consistent with more than one supported frame, including 143T and 145T. The reverse lookup intentionally returns multiple candidates rather than pretending that D and U uniquely identify the frame.
Next check: measure 2F. A 143T row uses 4 in while a 145T row uses 5 in, which separates the two references in this dataset.
Engineering References and Data Scope
Source checked August 16, 2026. Canonical dimensions are stored in inches; metric display values are calculated by multiplying by 25.4.
This page is a transformed lookup aid, not a reproduction of a complete standards table. NEMA MG 1 supplies the controlling standards context; ABB/Baldor-Reliance and WEG manufacturer references were used to verify the dimensional fields and frame-family distinctions shown here.
- NEMA — ANSI/NEMA MG 1-2021, Motors and GeneratorsControlling NEMA motor/generator standards basis; Part 4 is the dimension section referenced by NEMA’s MG 1 documentation. Copyright-protected standard.
- ABB / Baldor-Reliance — CA501 Standard Motor Catalog (2020)NEMA quick-reference chart on the inside back cover. ABB states the dimensions are for reference and directs users to the specific catalog-number drawing for exact dimensional data.
- WEG — NEMA Standard Dimensions technical posterIndependent manufacturer cross-check for NEMA dimensional nomenclature and T/U/original frame-program distinctions. WEG identifies its drawing as a dimension guide and flags manufacturer-specific fields.
- IEC — IEC 60072-1:2022Used only to define the NEMA/IEC boundary and IEC scope. IEC dimensional tables are not reproduced on this page.
Dataset and Source-Check Details
- Publisher
- Turn2Engineering
- Dataset label
- NEMA MG 1-2021 terminology / ABB CA501 2020 dimensional cross-check / WEG technical poster
- Included values
- D, E, 2F, H, U, V, BA for common current T/TS rows plus a limited legacy context set
- Calculated field
- Millimeters = inches × 25.4
- Missing values
- Em dash; never treated as zero
- Interpolation
- None. Frame dimensions are discrete reference values.
- Rights decision
- No complete standards/manufacturer table reproduction and no full CSV export
- Governing check
- Specific manufacturer outline drawing for the exact catalog number
Electric Motor Frame Size FAQs
It primarily identifies standardized mounting and shaft geometry; it does not by itself define the complete electrical rating, enclosure, overall length, or every manufacturer-specific feature.
Not automatically; verify the shaft details, mounting style, complete outline, enclosure, bearings, accessories, electrical ratings, and application requirements on the specific motor drawing.
T and U belong to different generations of NEMA frame programs, so similar numeric stems should not be treated as dimensionally interchangeable without checking the actual rows and drawings.
TS identifies a short-shaft variant for applicable T-frame families, making the shaft dimensions especially important to verify before replacement.
No. They are separate dimensional systems, so a cross-standard replacement requires an explicit dimensional and application check rather than matching frame numbers.
Use the Frame Chart as a Fit Check, Not a Purchase Approval
Use the frame designation and D/U dimensions to narrow the problem quickly, then confirm the base pattern, shaft geometry, mounting style, complete outline, and electrical duty on the exact replacement motor drawing. The interactive lookup is designed to make that dimensional check faster without implying that a frame-number match alone guarantees interchangeability.