Motor Nameplate Decoder
Decode NEMA motor nameplates and get wire gauge, conduit size, overload, and branch circuit breaker per NEC Article 430
Decode common AC motor nameplate fields such as horsepower, voltage, full-load amps (FLA), speed, frame, service factor, efficiency, enclosure, insulation class, and NEMA design letter. The app can show local expected-FLA, conductor, frame, insulation, enclosure, design, and efficiency screens, but those rows are source-gap planning prompts. It is not an NEC calculation of record, conductor schedule, conduit fill calculation, overload setting, breaker or fuse selection, starter/VFD approval, replacement approval, inspection approval, troubleshooting procedure, or safe-work authorization.
Screen motor slip and synchronous speed
Motor Slip & RPM Calculator →Check motor efficiency and operating cost
Motor Efficiency Calculator →Screen motor-start voltage-drop assumptions
Motor Starting Voltage Drop Calculator →Review nameplate source boundaries
Motor Nameplate Guide →How It Works
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Enter Motor Horsepower and Voltage
Input motor HP, rated voltage, and phase from the nameplate. The local expected-FLA screen is a comparison prompt only; verify the adopted code edition, selected motor, and manufacturer data before design use.
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Enter Nameplate Details
Input FLA, RPM, service factor, efficiency, frame size, enclosure, insulation class, and NEMA design letter. Treat each decoded field as a review note tied to the actual motor record.
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Review Local Screens
Review source-aware FLA deviation, conductor-row, frame, speed, service-factor, insulation, enclosure, design, and efficiency prompts. Do not treat local rows as licensed standard text or manufacturer-certified data.
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Separate Code And Product Decisions
Use adopted NEC text, local amendments, terminal ratings, conductor conditions, standard device sizes, time-current curves, controller/OCPD instructions, and AHJ requirements for final equipment decisions.
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Document Remaining Gaps
Record manufacturer drawings, model and serial data, VFD/starter context, hazardous-location listings, electrical safety controls, and qualified review before replacement, troubleshooting, or energized work.
Built For
- Electricians collecting nameplate fields before adopted-code and AHJ review
- Maintenance techs organizing replacement-motor source notes
- Plant engineers screening motor records before manufacturer review
- Inspectors and reviewers separating nameplate data from final code decisions
- Apprentices learning which nameplate fields need source verification
- Estimators flagging missing manufacturer, code, safety, and product data before takeoff
- Reliability engineers documenting motor specifications for maintenance records and CMMS
Features & Capabilities
Source-Aware Nameplate Fields
Screens HP, voltage, phase, FLA, RPM, service factor, efficiency, frame, enclosure, insulation, and NEMA design while keeping manufacturer and standard-source gaps visible.
Local FLA And Conductor Prompts
Shows expected-FLA and 125 percent conductor-row prompts for review notes only. It does not choose conductors, raceway, overloads, breakers, fuses, controllers, or standard device sizes.
Frame And Fit Warnings
Shows local frame and shaft cues while warning that shaft, keyway, foot bolt pattern, flange, coupling, enclosure, and manufacturer drawing data control replacement fit.
Service-Factor And Efficiency Boundaries
Flags service-factor and efficiency as selected-motor fields that need manufacturer, DOE/eCFR, NEMA, duty-cycle, ambient, and review context before operating or energy decisions.
Safety And AHJ Gaps
Carries NFPA 70E, OSHA, LOTO, arc-flash, shock, PPE, qualified-person, adopted-code, local-amendment, utility, and AHJ warnings into exports.
Source Pointers In Export
PDF and CSV exports carry the entered nameplate data, local screens, warnings, assumptions, residual gaps, and source-pointer IDs for review notes.
Comparison
| Screen Area | Local Prompt | Must Verify | Not A Final Output | Typical Review Use |
|---|---|---|---|---|
| FLA basis | Expected local row | Adopted code and selected motor | Conductor or OCPD sizing | Spot missing source data |
| Conductor row | FLA x 125 percent screen | Terminal, derating, raceway, voltage drop | Wire or conduit selection | Review prompt |
| Frame | Shaft cue | Manufacturer drawing and fit data | Drop-in replacement approval | Parts research |
| Efficiency | Label category screen | DOE/eCFR and manufacturer records | Compliance or savings proof | Energy review note |
| Safety | Warning list | NFPA 70E, OSHA, site program | Work authorization | Planning checklist |
Assumptions
- Nameplate fields are interpreted as typed and are not OCR, manufacturer, or field-measurement validated.
- Expected FLA, conductor, frame, insulation, enclosure, design, and efficiency rows are local source-gap screens.
- Adopted code, local amendments, manufacturer instructions, terminal ratings, derating, voltage drop, and AHJ requirements are not applied.
- Service factor and efficiency comments are review prompts, not continuous-overload, energy-savings, or replacement approvals.
- Electrical safety controls, LOTO, arc-flash, shock, PPE, and qualified-person requirements are outside the calculation.
Limitations
- Does not certify NEMA MG 1, DOE/eCFR, NEC, IEC, UL, CSA, or manufacturer compliance.
- Does not select conductors, raceway, overloads, OCPD, controllers, starters, VFDs, disconnects, labels, grounding, or replacement motors.
- Does not calculate voltage drop, available fault current, SCCR/AIC, time-current coordination, or standard device sizes.
- Does not verify hazardous-location listings, enclosure ratings, VFD/inverter duty, bearings, cooling, ambient, altitude, duty cycle, or driven-equipment fit.
- Does not authorize electrical testing, troubleshooting, LOTO, energized work, or safe operation.
References
- NFPA 70 (NEC) source pointer for motor-circuit context; local rows are not certified table reproductions.
- NEMA MG 1 source pointer for motors and generators; selected motor and manufacturer data still control use.
- DOE and eCFR electric-motor source pointers for efficiency and compliance context.
- NFPA 70E and OSHA electrical-safety source pointers for safe-work warnings.
Frequently Asked Questions
Learn More
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How to walk a rotating-equipment system from electrical supply through motor, transmission, and driven equipment, find which link is the problem, and pick the right field measurement to take next. Companion to the System Chain Analyzer.
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How to read supported Rosemount 3051SAL and 3051C model-code rows with context, seal, order, certification, configuration, and safety review gaps visible.
NEMA Enclosure Rating Guide: Types 1 to 13 Plus 7/9 Hazloc and the One-Way IP Cross-Reference
Plain-language guide to ANSI/NEMA Type ratings. Covers each active Type (1, 2, 3, 3R, 3RX, 3S, 3SX, 3X, 4, 4X, 5, 6, 6P, 7, 9, 12, 12K, 13) and historical Types 8 and 10. Why NEMA-to-IP cross-reference is one-way only, the assembly-rated-at-the-weakest-fitting rule, how NEMA 4X corrosion testing differs from IP66, and the field-truth substitutions that cause rework. Companion to the NEMA Enclosure Rating Decoder.
IP Rating Guide (IEC 60529): First Digit, Second Digit, K Suffix, and Supplementary Letters
Plain-language IP code reference with source limits: first digit, second digit, K suffix, supplementary letters, IP69K shorthand, why IPX9K is not NEMA 6P, and what tests IP does not include compared to NEMA.
IEC Motor Frame Guide: Frame Number Is Shaft Height, S/M/L Length, B3/B5/B14 Mounting, and the NEMA Cross-Reference
Plain-language IEC motor frame reference. The frame number is the shaft centre height in millimetres (IEC 60072-1); the S/M/L letter sets the body length and foot spacing, not the shaft height; the B3/B5/B14/B35 mounting codes; the 2-pole shaft-diameter reduction on frames 225 and larger; and why the IEC-to-NEMA cross-reference is nearest, not a drop-in. Companion to the IEC Motor Frame Decoder.
Hazardous Area Code Guide: NEC Class/Division vs IEC/IECEx Zone vs ATEX, and the Reversed Gas Groups
Plain-language hazardous-area marking reference. How the NEC Class/Division system, the IEC/IECEx Zone system, and the ATEX marking line up; why the gas groups run backwards (NEC Group A is IEC IIC); why a Division is not a single Zone; the temperature classes; and how to read an Ex string position by position with source-boundary warnings. Companion to the Hazardous Area Code Translator.
Wire & Cable Type Guide: What the Letters Mean, the "-2" Wet Rating, and the 110.14(C) Termination Trap
Plain-language wire and cable marking reference. The T/H/HH/W/N/X letter system; why the "-2" suffix is a 90 C wet rating, not a version number; the NEC 110.14(C) rule that a 90 C conductor is still sized from the 60 or 75 C termination column; NM-B and UF-B taken from the 60 C column; the flexible-cord letters; and AC versus MC grounding. Companion to the Wire & Cable Type Decoder.
Bearing Decoder Guide: Read SKF, FAG, Timken, NSK, NTN, Koyo Numbering
How to read a bearing part number across all six major makers. Bore code rule, suffix categories, intent-level cross-vendor translation, clearance class microns from ISO 5753-1, legacy brand aliases (Fafnir, MRC, Bower, RHP). Companion to the Bearing Part Number Decoder.
Motor Slip Source-Boundary Guide
What motor slip is, how synchronous speed relates to actual speed, NEMA design letter characteristics, and how to select the right motor design for your application.
Motor Nameplate Source-Boundary Guide
Field-by-field guide to reading electric motor nameplates. HP, FLA, frame size, insulation class, service factor, NEMA design, efficiency, and NEC wire sizing from nameplate data.
Motor Efficiency: Loading, Source Boundaries & Premium Comparison Review
How motor efficiency varies with load, why oversized motors waste energy, when to right-size, NEMA premium efficiency standards, and calculating annual energy savings.
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