<!-- Engineering logbook template · https://factalog.com/resources/engineering-logbook-template -->

# Engineering log entry

**Date:** YYYY-MM-DD
**Project:** Client · Project · Work package
**Engineer:** Name

## Work completed
- What you did today: analysis, testing, meetings, reviews.

## Design decisions
- **Decision:** One sentence a non-specialist could follow.

## Rationale
- The requirement, constraint, calculation or result that drove it.

## Alternatives considered
- Option: why it was rejected.

## Calculations / evidence
- Inline working, or the file name and revision of the calculation.

## Files / references
- Drawings, datasheets, standards, emails, with revision or date.

## Risks / unresolved issues
- Assumptions still to verify, and what happens if they are wrong.

## Next actions
- [ ] Action · owner · due date

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# Engineering log entry

**Date:** 2026-05-14
**Project:** Harbour Foods · Pallet conveyor upgrade · Drive frame
**Engineer:** A. Engineer

## Work completed
- Hand-checked drive frame cross-member for new 5.5 kW gearmotor (was 3 kW).
- Site visit: measured existing bolt pattern; photographed corroded base plate.

## Design decisions
- **Decision:** Replace the 50 × 50 × 3 SHS cross-member with 65 × 65 × 4 SHS.
- **Decision:** Keep the existing M16 8.8 hold-down bolts.

## Rationale
- Gearmotor reaction torque rises from 2.1 kN·m to 3.9 kN·m at the new rating.
- Conservatively taking the full reaction torque as bending in the cross-member:
  50 × 50 × 3 SHS φMs ≈ 3.2 kN·m → utilisation 1.22 (fails; was 0.66 at 3 kW).
  65 × 65 × 4 SHS φMs ≈ 7.1 kN·m → utilisation 0.55.
- Hold-down bolts at 3.9 kN·m: shear utilisation 0.41, no change needed.

## Alternatives considered
- Stiffen the existing 50 SHS with a welded plate. Rejected: clashes with the guard mounting, and site welding near food contact surfaces needs a permit window we don't have.
- Torque arm to the floor. Rejected: client does not want new floor fixings in the wash-down zone.

## Calculations / evidence
- Section capacities from the supplier's SHS tables, grade C350.
- Reaction torque from the gearmotor datasheet: 5.5 kW at 13.5 rpm output ≈ 3.9 kN·m.
- Site photos 2026-05-14 (IMG_2231 to IMG_2236).

## Files / references
- Gearmotor datasheet rev C.
- Drawing HF-CV-102 rev B (existing frame).

## Risks / unresolved issues
- Base plate corrosion: thickness not measured; assumed 10 mm nominal is still sound.
- Assumes the client confirms 5.5 kW is final (quoted alternative was 7.5 kW).

## Next actions
- [ ] Ultrasonic thickness check of base plate · workshop · 21 May
- [ ] Confirm motor rating in writing · client PM · 16 May
- [ ] Update HF-CV-102 to rev C · A. Engineer · 23 May