Definition
A device in an aircraft electrical system that monitors generator or alternator output voltage and disconnects the unit from the electrical bus if the voltage rises above a safe limit, preventing damage to electrical equipment and the battery.
Plain English
A safety device that watches the voltage coming out of the generator or alternator. If the voltage gets too high, it shuts the generator off so it can't damage the rest of the aircraft's electrical equipment.
Context Anchor
Seen in aircraft electrical-system maintenance and troubleshooting, especially around generators, alternators, voltage regulators, and charging-system faults.
Derivation
From 'over' (too much) + 'voltage' (electrical pressure) + 'protector' (something that guards against harm). The name describes exactly what it does: protects the system from too much voltage.
Why Pilots Care
A failed protector can allow regulator problems to destroy the battery or cause sudden loss of electrical power in flight.
Intuition Check
Do not think of an overvoltage protector as the same thing as a normal circuit breaker. A circuit breaker usually responds to too much electrical current; an overvoltage protector responds to electrical pressure that is too high.
Example Sentence 1
When the voltage regulator failed in flight, the overvoltage protector tripped and disconnected the alternator from the bus.
Example Sentence 2
When the regulator failed, the overvoltage protector opened the circuit and took the generator offline.