PROTECTIVE DEVICE FOR THREE-PHASE AC DYNAMO USED FOR CAR

摘要

PURPOSE: To protect a three-phase alternator against load damp phenomenon and overvoltage caused by a part mounted on an automobile by connecting the first terminal of an avalanche diode with a common terminal through a diode conducting forward when the avalanche diode is in avalanche mode. CONSTITUTION: A transitory overvoltage generated from several electronic apparatus in a vehicle is removed by connecting an avalanche diode 15 in parallel between terminals S<+> and S<-> . In practice, diodes D1 through D6 are biased such that a positive overvoltage generated at the terminals S<+> is not removed by Shockley diodes 11 through 13. Such an overvoltage brings the avalanche diode 15 into conducting state and a protective function for the avalanche diode 15 is provided by clipping the electric elements of the vehicle and a regulator.