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Fan Temperature Limits Ruler

Run the Fan Temperature Limits Ruler MicroSim Fullscreen

About This MicroSim

Every part of a hot fan carries its own temperature limit, and the lowest one wins. This ruler puts the limits from Chapter 20 on one horizontal temperature axis, 0°F to 1,200°F, so you can see where they overlap. Each row is one limit drawn as a range:

# Limit Range (°F) Source
1 Aluminum rotating parts, Arr. 4 centrifugal and Arr. 4 plug fans 0 to 250 FanPedia pp. 111, 114
2 Standard aluminum axial impeller 0 to 275 FanPedia p. 116
3 High temperature grease required, axial fans over 275 and above FanPedia p. 116
4 Shaft cooler recommended over 300 and above FanPedia p. 192
5 Arr. 4 centrifugal package 181 to 300 FanPedia p. 111
6-9 Centrifugal packages (Arr. 1, 8, 9, 9F, 10) 301-500, 501-600, 601-800, 801-1,000 FanPedia p. 110
10 Centrifugal package, engineering review 1,001 and above FanPedia p. 110
11 Type C centrifugal: steel funnel with rubbing band and rubbing bars 501 and above FanPedia p. 106
12 Nominally leak-tight construction recommended 0 to 600 FanPedia p. 120

Rows 1 and 5 are FanPedia's Arrangement 4 figures. Twin City Fan engineering (2026-10-09) advises that current practice does not use Arrangement 4 for high-temperature applications (standard ranges are typically up to about 180°F), so read those two rows as FanPedia's description, not a current ordering path.

A row is active at the marker temperature T when T lies in its range. "To" ranges include both ends (301 ≤ T ≤ 500), "over 275" means T > 275 and "over 300" means T > 300; open-ended rows have no upper bound and are labeled "and above". Active rows are drawn in full colour, with a ✓ and bold text in their axis label; inactive rows are dimmed but stay readable. The readout under the chart lists every active row in words.

Five questions follow, in a fixed order, one attempt each. When you submit, the marker jumps to the question's temperature, the row that decides it is outlined and marked ▶, and the feedback gives the reason. The question temperatures are illustrative design points chosen for practice. Mastery is 4 of 5 correct on the first attempt. Moving the marker is exploration and is never scored.

How to Use

  1. Move the temperature marker (it starts at 70°F, where rows 1, 2 and 12 are active) and watch which limits switch on and off. Hover or tap a bar for its full label, range and source.
  2. Read question 1, choose an option (click it or press 1-4) and press Submit (or Enter).
  3. Read the feedback: "Correct." or "Not quite." followed by the reason. The correct option is marked ✓ at once, and a wrong choice is marked ✗. The running score reads "Questions correct: n of 5".
  4. Press Next question and continue through question 5, then See summary for the first-attempt score, the mastery line and every question's reason. At 4 or more the summary adds "You can place a design temperature against the catalog limits."
  5. Press Start over to reset the questions, the score and the marker.

Keyboard: the arrow keys move the marker in 10°F steps; keys 1-4 choose an option; Enter submits, then goes to the next question; Tab reaches every control.

Data label: "Illustrative design temperatures · Limits: FanPedia pp. 106, 110, 111, 114, 116, 120, 192", shown under the chart.

Iframe Embed Code

You can add this MicroSim to any web page by adding this to your HTML:

<iframe src="https://moroshek.github.io/FanTASTIC-textbook/sims/ch20-fan-temperature-limits-ruler/main.html"
        height="1102px"
        width="100%"
        scrolling="no"></iframe>

Lesson Plan

Learning Objective

The learner will use FanPedia's temperature limits to decide, for five stated fans and design temperatures, which package, material or construction rule applies, answering at least 4 of 5 correctly (Bloom: Apply, verb: use).

Audience

Adult professional development: new application engineers, sales staff, representatives and facilities staff.

Duration

10-15 minutes

Prerequisites

  • High temperature construction and temperature packages
  • Maximum operating temperature
  • Aluminum construction
  • Shaft cooler and high temperature grease
  • Spark resistant Type C
  • Nominally leak-tight construction

All are introduced in Chapter 20 above the sim.

Activities

  1. Explore (3 min): Sweep the marker from 70°F to 1,200°F. Name the temperatures where a row switches on or off (250, 275, 300, 500, 600, 800, 1,000).
  2. Questions (6 min): Answer the five questions in order, committing each answer before the reason appears.
  3. Review (3 min): In the summary, find the row behind each reason on the chart.
  4. Discuss (3 min): Why do rows 1 and 2 end at different temperatures? At 600°F, is nominally leak-tight construction still recommended, and why does 650°F change the answer?

Common Misconceptions Addressed

  • One aluminum limit applies to every fan type: rows 1 and 2 end at 250°F and 275°F, side by side.
  • A temperature exactly at a boundary always belongs to the lower band: bands are inclusive as written, so 600°F is inside "0 to 600" and not "over 600°F".
  • If the package fits, nothing else needs checking: at 320°F the package row and the shaft cooler row are both active, and at 550°F the Type C funnel row switches on too.

Assessment

  • Running score "Questions correct: n of 5"; the summary shows "First-attempt score: n of 5" with "Mastery reached (4 of 5 needed)." or "Mastery needs 4 of 5 on the first attempt."
  • Follow-up: an Arrangement 4 centrifugal fan runs at 260°F. Which package applies, and may its impeller be aluminum?

References

  1. FanPedia: The Fan & Blower Encyclopedia - Twin City Fan. High temperature packages pp. 110-111 and 114, axial high temperature construction p. 116, Type C centrifugal p. 106, nominally leak-tight construction p. 120, shaft cooler p. 192.
  2. FanPedia (PDF edition) - Twin City Fan, the printable edition with the same page numbers.
  3. Chapter 20: Construction Classes, Materials and Spark Resistance - the chapter section this sim belongs to.
  4. Chart.js bar chart documentation - the floating-bar form used for the ranges.