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Torque-time duty arithmetic

Three-segment RMS torque

Inputs

Signed torque held constant for the stated first duration; zero and negative values are permitted.
Positive duration of the first user-defined duty segment.
Signed torque held constant for the stated second duration; zero and negative values are permitted.
Positive duration of the second user-defined duty segment.
Signed torque held constant for the stated third duration; zero and negative values are permitted.
Positive duration of the third user-defined duty segment.

Results

Declared duty-cycle time

4

Declared RMS torqueTrms

4.9497

Declared absolute peak torque

8

Declared signed mean torque

2.5

Trms = √[(T1²t1 + T2²t2 + T3²t3)/(t1 + t2 + t3)]

A first-pass number, not a code check, certification, or approval. Read the method and its limits below. What this is and is not.

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Method

Formula, when it applies, and when it does not

Calculate cycle time, absolute peak torque, and RMS torque from three signed torque/time segments without assessing motor thermal capacity.

Trms = √[(T1²t1 + T2²t2 + T3²t3)/(t1 + t2 + t3)]

When

  • Three explicitly declared duty segments
  • Constant torque within each segment
  • User-entered segment durations
  • Root-mean-square weighting

Don’t

  • This applies a three-segment root-mean-square torque relation to user-entered constant torque/time values. It does not derive an axis motion profile or load, determine motor/drive thermal capacity, compare torque-speed curves, infer a duty cycle, select a motor/drive, establish safety, suitability, or approval.
Kollmorgen RMS torque guidance