🌉 Newport Bridge Lift-Permit & Counterbalance Lab

Permit-to-lift board · balance, energy and maintenance diagnosis

PERMIT NOT ISSUED NORMAL PLANT

Live force board

Clearance0.0 mDeck + live load2700 tTotal counterweight2700 tUnbalanced force0 kNModel drive demand250 kNDrive stateLOW LOAD

Energy exchange audit

Span ΔGPE0 MJCounterweight ΔGPE0 MJModel drag work0 MJMotor / brake work0 MJ

Model convention: 1:1 rope travel and a labelled drag-force proxy. Real machinery is more complex.

1 · Learner route & prediction

Confidence before1–5

Each counterweight1350 t

Mechanical drag index1.0

Predict first, clear the road, then balance within the safe teaching band.

Run	CW	Load	Drive	Work

Use no more than three checks. The mission may contain a hidden plant fault.

No diagnostic check used.

What does the counterweight mainly reduce?

Choose a claim, then use: “In Run __, I changed __. The drive demand __ because …”

Metre-rule counterbalance · 5–8 minutes

Equipment: metre rule, stable pivot, two equal slotted masses or sealed mass bags, paperclip payload.
Keep feet clear; use small classroom masses only; teacher checks the pivot.

Confidence after1–5

What helped?Next route

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