Motor Torque - Power vs RPM Explained

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SUMMARY

A motor's nominal torque is defined at a specific RPM, and it varies with speed. For a variable speed motor rated at 3hp and capable of running from 0 to 3000 RPM, the torque must be calculated based on the rated power at the specified RPM. To accurately determine the available torque across different speeds, obtaining a torque curve from the motor vendor is essential.

PREREQUISITES
  • Understanding of motor specifications, including horsepower and RPM.
  • Knowledge of torque calculations and their relationship to power.
  • Familiarity with torque curves and their significance in motor performance.
  • Basic concepts of motor reducers and their applications.
NEXT STEPS
  • Research how to calculate torque from horsepower using the formula: Torque (lb-ft) = (Horsepower x 5252) / RPM.
  • Learn about obtaining and interpreting torque curves for different motor types.
  • Explore the impact of reducers on motor performance and torque output.
  • Investigate variable speed motor applications and their benefits in industrial settings.
USEFUL FOR

Engineers, motor technicians, and anyone involved in selecting or optimizing variable speed motors for industrial applications will benefit from this discussion.

stan
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hi

does anyone knows what exactly is a motor's nominal torque.

for example, if i have a variable speed motor that runs from 0 to 3000rpm and its rated power is 3hp, then are there various nominal torque for different rpms?

then which should i choose to if i need to connect it to a reducer?
thanks for any help.


stan
 
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The rated torque should be given at a specified RPM or the rated power should be given at a specified RPM to calculate the available torque. The torque will definitely vary as the speed changes. You need to get a torque curve for the motor to know exactly what you have to deal with. The vendor of the the motor will be able to provide that if you ask for it.
 

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