Calculating Continuous Torque Curve for Electric Motors?

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Discussion Overview

The discussion revolves around the calculation of a continuous torque curve for electric motors, focusing on the relationship between peak torque, rated torque, and how these values change with speed. Participants explore the implications of motor ratings and the factors influencing torque curves.

Discussion Character

  • Technical explanation, Conceptual clarification, Debate/contested

Main Points Raised

  • One participant expresses confusion about why the continuous torque curve begins to curve before the rated speed, suggesting that it should remain constant up to that point.
  • Another participant notes that not all motors are rated for continuous use, indicating that some may only deliver rated power intermittently, which could affect the continuous torque curve.
  • A further contribution suggests that calculating the continuous torque curve may not be straightforward without access to the motor's thermal properties and efficiency data, which are typically available to manufacturers.

Areas of Agreement / Disagreement

Participants generally agree on the concept that continuous torque may not remain constant up to rated speed, but there is no consensus on how to calculate the continuous torque curve or the implications of different motor ratings.

Contextual Notes

Limitations include the dependence on specific motor characteristics, such as thermal properties and efficiency, which are not universally available or defined in the discussion.

AmazingTrans
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Hi there,

I have a motor peak torque, peak power, peak speed, rated torque, rated power, rated speed, torque at max speed.

I was able to produce the peak torque curve.
But, i don't understand how to create this continuous torque curve here. I have attach a link here, and somehow the continuous torque starts curving before the rated speed?

I thought, the torque for the "continuous torque curve" should remain constant up to the rated speed then only start curving? I seen a lot of motor does the same. What formula should i use to calculate this curve/

Power = 2*3.142*torque * speed

Electric-motor-performance-courtesy-McLaren-Electronic-Systems.jpg

http://current-e.com/wp-content/upl...mance-courtesy-McLaren-Electronic-Systems.jpg

AT
 
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Norton blocks my access to that page but..

Not all motors are rated for continuous use. Many are rated for intermittent use. In other words they might be able to deliver the rated power at the rated speed intermittently but not continuously. If you try to use them at max load continuously they may overheat.
 
yup, i understand the concept.
I'm just wondering how to plot the continuous torque curve.
 
I'm not sure it can be calculated easily. If you were the motor manufacturer you would have access to its thermal properties. That would allow you to work out how much power the motor can be allowed to dissipate as heat. That and data on the efficiency of the motor would tell you how much power and torque the motor can be allowed to deliver continuously at any given speed.
 

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