Definition
A piece of soft iron or other ferromagnetic material placed near a permanent magnet to divert a portion of the magnetic flux away from the working air gap. By bypassing some of the flux, the shunt reduces the field strength acting on the moving element of an instrument, allowing the instrument to be calibrated and compensated for temperature changes.
Plain English
A small piece of iron placed near a magnet to soak up some of its magnetic pull. This lets engineers fine-tune how strong the magnet feels to the rest of the instrument, so readings stay accurate.
Context Anchor
Seen in descriptions of aircraft instruments, electrical components, and other devices that use permanent magnets or controlled magnetic fields.
Derivation
Shunt comes from the old English meaning 'to turn aside' or 'divert.' In electrical work it already means a path that carries part of a current around something else. A magnetic shunt does the same thing for magnetic flux instead of electric current.
Why Pilots Care
Accurate instrument readings depend on proper magnetic flux; an unadjusted shunt can cause false electrical or directional indications.
Analogy
It is like opening a side road for traffic. Some of the flow takes the easier side route, so less goes through the main route.
Intuition Check
Do not assume a magnetic shunt is an electrical shunt carrying current. In this term, it redirects part of a magnetic field.
Example Sentence 1
A magnetic shunt inside the tachometer generator helps keep the indication accurate as cockpit temperatures change.
Example Sentence 2
Compass swing procedures sometimes require a magnetic shunt to offset local magnetic interference inside the cockpit.