Inlet Box Position Trainer¶
Run the Inlet Box Position Trainer MicroSim Fullscreen
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About This MicroSim¶
An inlet box position names where the box opening sits on a dial drawn on the fan as seen from the drive side: 360 at the top, numbers increasing clockwise in 45° steps (FanPedia p. 144). The position does not change with rotation or discharge.
| Position | FanPedia description | Opening (drive side) |
|---|---|---|
| 45 | Angular down intake | Upper right |
| 90 | Horizontal right intake | Right |
| 135 | Angular up intake | Lower right |
| 180 | Bottom up intake | Bottom |
| 225 | Angular up intake | Lower left |
| 270 | Horizontal left intake | Left |
| 315 | Angular down intake | Upper left |
| 360 | Top down intake | Top |
A picture drawn from the inlet side mirrors left and right, so the drive-side position is 360 − p, where p is the angle read on the inlet-side picture (0 is written 360; 180 stays 180).
The sim shows eight illustrative installations in a fixed order: four drive-side views, three inlet-side views and one text-only description. Each picture is an end view of a fan housing with its inlet box, a viewpoint label and an arrow showing the air entering the box. You choose one of the eight positions and press Check. You get two attempts: a wrong first answer gets a hint that names the slip (for example an inlet-side picture read without mirroring) but not the position, and a second wrong answer reveals the position with its explanation and counts as missed. When an item is resolved, the drive-side dial is drawn over the picture with the answer highlighted; an inlet-side picture first flips to the drive side, and a dashed outline marks where the box appeared before the flip.
"Positions correct: n of 8" counts first-attempt answers only. Mastery is 7 of 8 on the first attempt. After item 8, free practice unlocks: drag the box around the housing (or use Turn and the arrow keys) and switch the viewpoint. Free practice is never scored.
How to Use¶
- Read installation 1, note the viewpoint label, and choose a position with the 45 to 360 buttons (or keys 1-8).
- Press Check (or Enter). A correct answer reads "✓ Correct: position n, description." A wrong one reads "✗ Not quite." with a hint; use the second attempt.
- Press Next installation (or Enter) and continue through item 8, then press See score.
- In free practice, move the box and press View to switch between the drive side and the inlet side. Notice that switching the view changes 90 to 270 and 45 to 315 on the picture, while 360 and 180 never change. Start over clears the score and returns to item 1.
Keyboard: keys 1-8 choose 45 to 360; Enter checks, then goes to the next item. In free practice the left and right arrow keys turn the box and V switches the view. Tab reaches every button.
Data label: "Illustrative installations · Source: FanPedia p. 144", at the bottom left of the drawing.
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/ch18-inlet-box-position-trainer/main.html"
height="647px"
width="100%"
scrolling="no"></iframe>
Lesson Plan¶
Learning Objective¶
The learner will apply the drive-side viewing convention to assign the correct inlet box position (45, 90, 135, 180, 225, 270, 315 or 360) to eight described or pictured installations, including views drawn from the inlet side (Bloom: Apply, verb: apply).
Audience¶
Adult professional development: new application engineers, sales staff, representatives and facilities staff.
Duration¶
10 minutes
Prerequisites¶
- Inlet box and inlet box position (Chapter 18)
- Drive side and inlet side (Chapter 12)
Activities¶
- Installations (5-6 min): For each item, say aloud which side the picture is drawn from before choosing a position.
- Free practice (3 min): Put the box at 90, switch to the inlet side and read the picture; then repeat for 45, 180 and 360.
- Transfer (1-2 min): Rework the chapter example "Elbow or Inlet Box?" (duct from the ceiling) and confirm position 360.
Common Misconceptions Addressed¶
- The position can be read from either side: items 5, 6 and 8 are inlet-side pictures, and each one flips to the drive side when it is resolved.
- 45 and 315 (or 135 and 225) are interchangeable: item 3 is upper left (315), and the feedback points out that 45 is upper right.
- 180 means the box faces up because the air moves up: items 4 and 7 have the opening at the bottom, and the number names where the opening is.
Assessment¶
- "Positions correct: n of 8" counts first-attempt answers; mastery is 7 of 8. The summary shows the first-attempt score, the mastery line and the missed items.
- Moving the box in free practice is not evidence of mastery. Ask the learner to explain why 180 and 360 are the only positions that read the same from both sides.
References¶
- FanPedia: The Fan & Blower Encyclopedia - Twin City Fan's reference; p. 144 gives the inlet box position descriptions and states that positions are determined from the drive side.
- Twin City Fan & Blower - current catalogs and drawings showing inlet box options on centrifugal fans.
- Centrifugal fan - Wikipedia overview of centrifugal fan construction, housings and inlets.