Hoist motor
Lifts the load vertically and must handle gravity load, starting torque, holding brake integration and frequent starts.
Check: SWL, reeving, hoist speed, duty, starts/hour, brake torque and thermal rating.
For buyers checking crane motor offers
EOT Crane Motor Selection Guide
Motor kW is only the first check. A crane motor must also match duty, starts per hour, torque, speed, brake, gearbox, control method, ambient conditions and protection requirements.
Beginner answer
A crane motor should not be selected only from calculated kW. Ask the supplier to confirm kW, speed, torque, duty, starts per hour, insulation class, enclosure, ambient rating, brake/VFD compatibility, service factor and datasheet for each motion.
Motor by crane motion
Different crane motions stress motors differently
A hoist motor, cross-travel motor and long-travel motor may all be called "crane motors," but they face different loading and control problems.
Cross-travel motor
Moves the trolley/hoist across the bridge. Acceleration, positioning and smoothness often matter more than steady power.
Check: trolley mass, load, CT speed, acceleration time, VFD need and wheel/rail condition.
Long-travel motor
Moves the complete bridge along runway rails. It is sensitive to skew, rail alignment, wind, friction and synchronization.
Check: bridge mass, LT speed, runway condition, wheel loads, drive arrangement and anti-skew needs.
Selection inputs
Information needed before accepting a motor selection
Power and speedRated kW/HP, motor rpm, gearbox ratio, output speed and whether the value is standard or calculated.
Duty and startsStarts per hour, load spectrum, operating hours, duty class and expected thermal behavior.
Torque marginStarting, pull-up, pull-out and low-speed torque need verification, especially with VFDs.
Thermal and ambient ratingInsulation class, temperature rise, ambient temperature, cooling, altitude and enclosure protection.
Control methodContactor, pole-changing, VFD, soft start or other control affects motor and brake selection.
Brake compatibilityHoist and travel brakes must match motor shaft, torque, control sequence and emergency stopping need.
BOM and quotation control
Motor details that should be visible in the vendor offer
| Motor item | Ask the supplier to state | Why it matters | Red flag |
|---|---|---|---|
| Motor make and model | Manufacturer, frame size, rated kW, rpm, mounting and datasheet. | Confirms whether two offers use comparable equipment. | Only "standard motor" stated. |
| Duty and thermal rating | Duty designation, starts/hour, insulation class, temperature rise and ambient rating. | Prevents overheating and premature winding failure. | No starts/hour or duty basis. |
| Torque capability | Starting torque, pull-out torque, VFD low-speed torque and margin basis. | Crane motors need torque, not just kW. | Only steady-state kW calculation provided. |
| Protection and enclosure | IP rating, cooling method, terminal box position, cable entry and hazardous/corrosive suitability if needed. | Wrong enclosure causes environmental and maintenance failures. | Outdoor/dust/corrosion environment ignored. |
| Brake and control interface | Brake type, rectifier/control sequence, VFD compatibility, DBR/regenerative braking scope. | Motor, brake and drive must work as one system. | Brake/VFD responsibility split between vendors. |
Buyer mistakes
Common crane motor selection mistakes
Using kW only
Calculated kW can be acceptable while torque, thermal rating or starts/hour are still wrong.
Ignoring duty
A light-duty motor in a frequent-cycle crane can overheat even if the capacity appears correct.
Forgetting brake integration
The motor, brake, rectifier, contactor/VFD and emergency stop sequence must be compatible.
Skipping environment checks
Dust, heat, outdoor use, corrosion and washdown affect enclosure, cooling and terminal protection.
Assuming VFD solves everything
VFDs improve control but introduce braking energy, low-speed cooling and insulation compatibility checks.
Not asking for datasheets
Without datasheets, the buyer cannot verify duty, torque, insulation or equivalent substitution.
Related tools and guides
Use these next while reviewing the motor offer
Engineering boundary: This guide supports preliminary RFQ and quote review. Final motor selection, torque verification, thermal rating, protection and control integration must be confirmed by competent engineers and supplier datasheets.
Next action
Ask for the motor data sheet before comparing price
A quote with kW only is incomplete. Request duty, torque, insulation, enclosure, brake/control compatibility and datasheets for each motion.