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Electric Motors & Drives replacement guide

Compare AC and DC motors, gearmotors, servo motors, drives, starters, and motor controls using the nameplate and complete mechanical and electrical interface.

Evidence boundary. A nominal horsepower and frame match is not automatically a drop-in replacement. Verify torque, speed, enclosure, mounting, shaft, controls, brake, and feedback requirements.
Items covered01 · 16 component types
  • AC motors
  • DC motors
  • Gearmotors
  • Servo motors
  • Stepper motors
  • Brake motors
  • Explosion-proof motors
  • Washdown motors
  • Vertical motors
  • Spindle motors
  • Variable-frequency drives
  • Soft starters
  • Motor starters
  • Overload relays
  • Motor brakes
  • Motor encoders
What to capture02
Manufacturer, model, frame, and enclosureRecord this before searching for a substitute.
Horsepower or kW, voltage, phase, and frequencyRecord this before searching for a substitute.
RPM, service factor, efficiency, and dutyRecord this before searching for a substitute.
Shaft, flange, mounting, brake, and encoderRecord this before searching for a substitute.
Drive, starter, feedback, and control requirementsRecord this before searching for a substitute.
What must match03
Electrical compatibilityConfirm it against the original equipment, duty, and source documentation.
Frame, shaft, flange, and mountingConfirm it against the original equipment, duty, and source documentation.
Speed-torque curve and dutyConfirm it against the original equipment, duty, and source documentation.
Environment and enclosureConfirm it against the original equipment, duty, and source documentation.
Drive, brake, feedback, and controlsConfirm it against the original equipment, duty, and source documentation.
Common searches04
What motor replaces this frame?
How do I read a motor nameplate?
Can I replace a motor with a different efficiency class?
What changes when a motor is used with a VFD?
Authoritative starting points05
ABB low-voltage motorshttps://new.abb.com/motors-generators/low-voltage-motorsGrainger motors and power transmissionhttps://www.grainger.com/category/power-transmission
Manufacturer-backed ODP / AEGIS lookup690 WEG catalog records
WEG three-phase ODP and internal-AEGIS motor lookup

Browse exact WEG 2026 catalog identities with RPM, frame, voltage, enclosure/product-group context, and exact source-row provenance.

Browse 690 WEG ODP / AEGIS motors →
Live manufacturer single-phase/SP4 lookup400 Baldor-Reliance records
Baldor-Reliance single-phase and SP4 general-purpose motor lookup

Browse exact current single-phase enclosed/open and SP4 three-phase catalog numbers with live manufacturer detail evidence for output, speed, phase, voltage/current, frame, enclosure, efficiency, service factor, mounting, duty, insulation, and VFD status.

Browse 400 Baldor-Reliance single-phase/SP4 motors →
Live manufacturer open-motor lookup396 Baldor-Reliance records
Baldor-Reliance general-purpose three-phase open motor lookup

Browse exact current open-motor catalog numbers with live manufacturer detail evidence for output, speed, frame, enclosure, voltage/current, efficiency, service factor, duty, mounting, insulation, and VFD status.

Browse 396 Baldor-Reliance open motors →
Live manufacturer motor lookup400 Baldor-Reliance records
Baldor-Reliance general-purpose three-phase enclosed motor lookup

Browse exact current catalog numbers with live manufacturer detail evidence for output, speed, frame, enclosure, voltage/current, efficiency, service factor, duty, mounting, insulation, and VFD status.

Browse 400 Baldor-Reliance motors →
Manufacturer-backed motor lookup331 WEG 2026 catalog records
WEG three-phase general-purpose TEFC motor lookup

Browse exact 2026 WEG catalog numbers by horsepower, RPM, NEMA frame, voltage, service factor, full-load current, efficiency, C dimension, and source row.

Browse 331 WEG three-phase motors →
Related lookup guides1 workflow
electric motor replacement by nameplate

Electric motor replacement by nameplate: what must match

Capture the complete nameplate, frame and shaft geometry, enclosure, duty, and control requirements before selecting a replacement motor.

Open guide →
Source-backed field guides1 guide
Motors & drives

Electric motor replacement

A practical motor replacement checklist covering frame, shaft, mounting, voltage, phase, frequency, horsepower, speed, enclosure, duty, and VFD requirements.

Open guide →
Search the verified catalogIdentify an unknown part