The warming circuit breaker.

Why does an overload take time to trip a breaker?

Setting up the mechanism…

Contact current: 0.00A
Bimetal heat / trip heat: 0.000
Contact: Closed

Calculated trip time: No finite thermal trips

Fit the trip mechanism and apply the test current

Why does an overload take time to trip a breaker?

Resistive heat bends the bonded strip. Its two metals expand differently, moving the latch until the contact spring snaps the circuit open.

h(t) = (I/16 A)²(1 − e^(−t/30 s)); trip at h ≥ 1

What this model simplifies

Illustrative thermal-only breaker: 30 s thermal time constant, trip at normalized heat 1, equilibrium heat (I/16 A)². The latch stays tripped while the disconnected strip cools. It is not a certified breaker time-current curve; magnetic short-circuit trips are outside this model.

Read the source · eaton.com ↗

Put it to work.

Trip the contact with a sustained 24 A overload on a 16 A breaker.

Make it work.

Find when an overload trips the breaker.

Run

Fine adjustments 2

Applied currentA

Overload durations

The warming circuit breaker.

Why does an overload take time to trip a breaker?

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Figuvo

Understand by doing.

Understanding is something you do.

Figuvo is a place to look inside everyday things, build a connection, and discover the idea behind them.

177 interactive experiments. Each has a working model and a challenge to test what you found.

The original inspiration

Levers & fulcrums The surprising gyroscope The field cannon Inside the human body

Original demonstrations by The Bugged Dev. The teaching models and interactions here are new implementations.

Community builds

New teaching models inspired by public builds shared around Anatomy.

Anatomy · the original announcement How a rocket pushes through space · Gustavo Inside a tactile key switch · @retaqib Pressure through the coffee bed · Gustavo The overbalance wheel · Shawn A seconds pendulum clock · @Baconbrix Three feet on the ground · Soju Inside a layered particle detector · Yash A double-deck pressure cabin · Charlie Leave the spent booster behind · @quantapar Principal, interest and escrow · Sean Gear a Martian year · @samani_Two balls in, two balls out · @samani_Two slits, one probability pattern · @samani_Join through a clear plastic cover · Josh Brown Lay pipe without a sharp bend · @Phi10w Eight cylinders and a blower · @love4hxns Four columns under a Joglo roof · Nur Asyrof An office for dependent tasks · Yaroslav Yablonski One image, six editable layers · Meng To The Redis caching machine · @uviii_03 Inside the Sony CMD-J5 · Ann Afterburner thrust stand · Joshua Guo Open-back headphones · Surajan Shrestha Two-thread lockstitch machine · @slashui Signal factory · Dhruval Golakiya

Everyday electrical

The warming circuit breaker.

Why does an overload take time to trip a breaker?

Setting up the mechanism…

Contact current: 0.00A
Bimetal heat / trip heat: 0.000
Contact: Closed

Calculated trip time: No finite thermal trips

Fit the trip mechanism and apply the test current

Why does an overload take time to trip a breaker?

Resistive heat bends the bonded strip. Its two metals expand differently, moving the latch until the contact spring snaps the circuit open.

h(t) = (I/16 A)²(1 − e^(−t/30 s)); trip at h ≥ 1

What this model simplifies

Read the source · eaton.com ↗

Put it to work.

Trip the contact with a sustained 24 A overload on a 16 A breaker.

Make it work.

Find when an overload trips the breaker.

Run

Fine adjustments 2

Applied currentA

Overload durations