Definition
The electrical current carried into and out of the spinning rotor winding of a wound-rotor (slip-ring) AC generator or motor by means of slip rings and stationary brushes. Because the rotor is rotating, the current cannot be delivered through fixed wires; instead, the brushes ride on continuous metal rings mounted on the rotor shaft, providing a sliding electrical contact that allows current to flow between the stationary external circuit and the rotating winding.
Plain English
The electricity that flows in and out of the spinning coil inside a generator or motor. Since the coil is turning, the current is passed through metal rings on the shaft and small carbon blocks that press against them, so the wires don't have to twist.
Context Anchor
Seen in aircraft electrical system discussions, especially when learning how alternators, generators, voltage regulators, brushes, and slip rings work together.
Derivation
Current comes from a Latin word meaning “to run.” In electricity, it means electric charge running through a path. Rotor means the part that rotates, and winding means wire wound into a coil. Together, the phrase points to electric flow running through a coil on a rotating part.
Why Pilots Care
Without proper current flow through the rotor winding the alternator cannot produce usable electrical power, risking battery depletion and loss of critical avionics and instruments.
Grounding Statement
The rotor winding is a spinning coil that becomes a magnet only when electric current flows through it.
Intuition Check
Current here means electric flow, not airflow, water movement, or present time. “Into and out of” means the electricity has a complete path through the rotor winding, not that the winding stores the electricity.
Example Sentence 1
The slip rings and brushes carry the current into and out of the rotor winding without twisting the wires as the rotor turns.
Example Sentence 2
Low current into and out of the rotor winding caused the alternator output to drop during the preflight electrical check.