Definition
An auxiliary set of coil windings inside an aircraft magneto that produces a brief, high-intensity spark to the spark plugs during engine start. It works in conjunction with an impulse coupling or a starting vibrator to deliver a strong, retarded spark at low cranking speeds, when the magneto's normal output would be too weak to reliably ignite the fuel-air mixture.
Plain English
Extra wire coils inside the magneto that give the spark plugs a strong jolt while the engine is being started. They make sure the engine fires up cleanly even though the magneto is turning slowly during cranking.
Context Anchor
Seen in aircraft electrical system maintenance, especially when studying generator voltage regulators and generator control units.
Derivation
From Latin 'accelerare' meaning 'to hasten or speed up.' The winding 'accelerates' or boosts the spark energy during the slow turning speeds of engine start, when the magneto would otherwise be too sluggish to fire properly.
Why Pilots Care
Ensures reliable engine starting, especially in cold weather or with marginal battery power, reducing the risk of backfiring or incomplete combustion during startup.
Intuition Check
Accelerator does not mean the engine throttle here. It means a coil that speeds up the action of an electrical regulator.
Example Sentence 1
The mechanic traced the hard-start problem to a failed accelerator winding in the left magneto.
Example Sentence 2
A weak accelerator winding can cause hard starting even when the main magneto coils test within limits.