Patent ID: 6031701
Filing Date: 2000-02-29
Classification: H02H,H02P

Abstract:
An overvoltage protective device, to protect an electrical installation from overvoltage, which installation has an onboard power supply system including an electrical generator and a generator voltage regulator for controlling the output voltage of the generator and having power and reference leads fed by the electrical generator and electrical devices connected thereto, said device comprising:a basic unit connected in parallel with the onboard power supply system at the output side of the generator, with said unit having at least one power circuit branch connected in parallel with the onboard power supply system across the power and reference leads, a voltage detecting unit and an actuating unit, said power circuit branch including at least two resistance components, with at least one of the resistance components being controllable to reduce its resistance and said voltage detecting unit and said actuating unit including circuit means for monitoring the voltage of the power supply and for controlling the at least one controllable resistance component to reduce its resistance and fixedly set the power supply voltage to a limiting threshold value V.sub.BMAX when the power supply voltage exceeds the limiting threshold value (V.sub.Bmax), which value is above the rated voltage of the system generator; and wherein said basic unit further includes a voltage feedback unit, which is connected to said circuit means, for emitting a control signal to the generator voltage regulator to cause a reduction of the generator excitation voltage if an overvoltage is detected; andwherein the voltage system is a vehicle onboard power supply system having said generator and an energy store connected in parallel.