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Component selection · Torque ratings

Stall, peak and continuous torque: what can you compare?

Before comparing torque numbers, identify what each number measures. Keep the exact motor or actuator, the manufacturer’s rating label and its operating conditions together. A stall figure alone does not establish sustained output in your robot.

Sources checked

Start with the label, then read its definition.

Rating labels answer different questions
LabelHow to read itWhat it does not establish
StallFor the ROBOTIS example below, a maximum momentary output at zero speed. Read the electrical conditions and performance information. ROBOTIS explanationA continuous operating capability or a torque available throughout the speed range.
PeakA source-defined limit. Tecnotion’s example states a magnet-temperature rise condition. Tecnotion conditionsA universal time allowance. Do not invent a number of seconds from the word “peak.”
ContinuousA rating with a thermal and mounting basis. Read the footnotes as part of the value. Tecnotion footnote 1The same output under a different installation or thermal condition.

The sources use different tests. These examples explain how to read a specification; they do not rank the products or establish that the products are substitutes.

Build a comparison you can trace.

For each shortlist entry, record the following alongside the torque value. If a field is missing, keep it marked unknown and ask the supplier rather than silently making the rows equivalent.

  1. Exact configuration. Record the full model, winding or option, and whether the statement belongs to the individual model or its series.
  2. Document identity. Save the original source link, revision and page or table. A similarly named model in another document is not enough.
  3. Rating and units. Retain the original label and unit. Keep motor-side and output-side quantities separate where the source distinguishes them.
  4. Operating point. Ask which voltage, current basis and speed accompany the published torque. Preserve the manufacturer’s qualifiers.
  5. Thermal conditions. Record the temperature, mounting and cooling conditions supplied with the rating.
  6. Your duty requirement. Describe the torque and speed over time, including pauses and acceleration, so the supplier can assess the intended use.

A useful comparison row is: exact model → torque label and value → source conditions → document locator → open questions. Keep unmatched conditions visible instead of presenting one apparently comparable torque column.

Two examples from original documents

ROBOTIS XH540-V150-R

The eManual lists stall torque of 6.4 N·m at 24 V and 2.4 A. Its performance note distinguishes stall from continuous output and explains that the performance curve uses a gradually increasing load.

Keep the label “stall.” The cited row does not supply a continuous-torque value, and this guide does not derive one using an assumed percentage.

Open the exact model recordRead the ROBOTIS eManual

Tecnotion QTR-A-65-17

The QTR65 sheet separates peak and continuous ratings and attaches conditions to each. Read its exact model column and footnotes together.

The model record includes a bounded reading of revision 2.4. Confirm your installation and duty with the supplier before using it in a shortlist.

Read the model’s rating conditionsOpen the QTR65 sheet, page 1

When the conditions do not match

Leave comparability unresolved. Ask for the applicable curve or written rating basis for your configuration. Do not convert stall into continuous torque, assign an undocumented peak duration, or call two components interchangeable on the strength of one number.

When requesting a quote, include the exact model, quantity, supply and drive, mounting/cooling arrangement, speed and duty requirement, and the source revision you used.

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Original sources and corrections

  1. ROBOTIS XH540-V150-R eManual — Specifications and the note below the performance comparison table.
  2. Tecnotion QTR65 specification sheet, revision 2.4, page 1 — rating rows and footnotes. Document identity: a0172fa9e84d6fe213f75b3fbf1f5a681d4ff30ef6e8c6a83828060dc9685e9f (SHA-256).

These are source readings, not supplier approval or an application-suitability assessment.

Report a correction with a source