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A conductor passing through a ring winding.
Also known as: CT, Current instrument transformer, Ring core transformer, Wire through a ring
A current transformer measures a large current by inductive coupling to a small one, and its secondary must never be left open-circuited while the primary is live — the induced voltage can reach lethal levels. That is the single most important operational fact about the device.
Denotes a current transformer: an instrument transformer producing a secondary current proportional to a large primary current.
Contexts: Electrical equipment
Must have its secondary either burdened or short-circuited while the primary carries current, because an open secondary develops a dangerously high voltage.
Contexts: Electrical equipment
Is drawn with the primary conductor passing through a toroidal secondary, which is how the physical device is usually built.
Contexts: Electrical equipment
A straight conductor line passing through the centre of a circle, with two leads from the circle.