System for preventing damage to a battery charger due to application of a battery with wrong polarity
First Claim
1. In an automotive electrical system includingan alternator having an exciter winding, exciter diodes connected to said exciter winding, a positive exciter terminal (D+), a positive rectified alternator output terminal (B+), and a negative rectified alternator terminal (B-), connected to a reference potential,a battery (B) having a negative terminal (A-) connected to said reference potential and a positive terminal (A+);
- a starter motor (M);
and starter switch means (S2, C2, K2) connected to said battery so that said motor is started upon activation of said starter switch means independent of the polarity of said battery,apparatus for protecting said system from application of a voltage having a polarity opposite the polarity of said battery comprisinga control switch S1;
a protective diode (D3) conductive only when the polarity of the DC voltage is of the predetermined polarity of said battery,switch means including a relay (C1, K1) comprising a relay coil (C) connected in series with said protective diode and the control switch (S1) and a pair of relay contacts (K1) operative on the control of said relay coil and connected in series with the terminals (A+, A-) of said battery;
the relay coil being connected to said system and to said blocking diode for connection of DC voltage to, and disconnection of DC from said system when said blocking diode is, respectively, conductive or non-conductive with respect to said polarity of the battery;
and further comprising an auxiliary relay (C7, K7) having a coil connected between said positive exciter terminal (D+) and said reference potential (B-, A-),and a pair of auxiliary relay contacts (K7) connected in series with the relay coil (C1) of said first relay (C1, K1).
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Accused Products
Abstract
The electrical system of a motor vehicle is protected against damage due to voltage sources, either the own battery or an external source, connected with wrong polarity by the combination of a diode and relay switches. In one embodiment, the diode is connected to the battery so that current flows only when the battery is connected with the correct polarity. The relay coil connected in series with the diode controls contacts which connect the battery to the rest of the circuit only when current flows through the diode. Alternatively, or in conjunction with this type of circuit, a shunting diode can be provided through which current flows only when the battery is connected with incorrect polarity. When current flows through this shunting diode, it also flows through the contacts of excess current cutout which then open to disconnect the battery from the remainder of the circuit.
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Citations
12 Claims
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1. In an automotive electrical system including
an alternator having an exciter winding, exciter diodes connected to said exciter winding, a positive exciter terminal (D+), a positive rectified alternator output terminal (B+), and a negative rectified alternator terminal (B-), connected to a reference potential, a battery (B) having a negative terminal (A-) connected to said reference potential and a positive terminal (A+); -
a starter motor (M); and starter switch means (S2, C2, K2) connected to said battery so that said motor is started upon activation of said starter switch means independent of the polarity of said battery, apparatus for protecting said system from application of a voltage having a polarity opposite the polarity of said battery comprising a control switch S1; a protective diode (D3) conductive only when the polarity of the DC voltage is of the predetermined polarity of said battery, switch means including a relay (C1, K1) comprising a relay coil (C) connected in series with said protective diode and the control switch (S1) and a pair of relay contacts (K1) operative on the control of said relay coil and connected in series with the terminals (A+, A-) of said battery; the relay coil being connected to said system and to said blocking diode for connection of DC voltage to, and disconnection of DC from said system when said blocking diode is, respectively, conductive or non-conductive with respect to said polarity of the battery; and further comprising an auxiliary relay (C7, K7) having a coil connected between said positive exciter terminal (D+) and said reference potential (B-, A-), and a pair of auxiliary relay contacts (K7) connected in series with the relay coil (C1) of said first relay (C1, K1). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification