US 2020/0006935 A1 · DC POWER SYSTEM BREAKER FOR TRANSPORTATION VEHICLE

Abstract

A thermal hazard protection circuit for a transportation vehicle comprises an interruptible power circuit connected between a power source and load, and a failsafe circuit operative to permanently interrupt current flow under an overcurrent condition. The interruptible power circuit comprises a Positive Temperature Coefficient (PTC) component in series with bi-stable relay configured as a SPST switch. The failsafe circuit comprises a failsafe relay energized by current in the interruptible power circuit. An input of the failsafe relay is connected to the battery, and a normally closed (NC) output (not connected to the input so long as the failsafe relay is energized) is connected to a control input of the bi-stable relay that opens the SPST switch. In an overcurrent condition, the PTC component limits current flow, switching the failsafe relay input to its NC outputs, providing a control signal to open the SPST switch, rendering the interruptible power circuit non-conductive and isolating the load.

Claims13

Dependent claims

A thermal hazard protection circuit for a transportation vehicle including a battery having positive and negative terminals, and one or more loads, comprising:

an interruptible power circuit connected between the battery and the load, the interruptible power circuit comprising:
a first positive temperature coefficient (PTC) component operative to limit current through the interruptible power circuit to a first predetermined current value in response to heat in excess of a first predetermined thermal value;
and
a bi-stable relay connected in series with the first PTC component and operative to selectively open or close the interruptible power circuit;
a failsafe circuit connected between the interruptible power circuit and a first control input of the bi-stable relay operative to cause the bi-stable relay to open the interruptible power circuit in response to the first PTC component limiting current through the interruptible power circuit.

2 more elements

A method of protecting a transportation vehicle electrical circuit, comprising a battery having positive and negative terminals and one or more loads, from thermal hazard, comprising:

directing current from the battery to the load through an interruptible power circuit connected between the battery and load, the interruptible power circuit comprising a series connection of a first positive temperature coefficient (PTC) component, operative to limit current to a first predetermined current value in response to heat in excess of a first predetermined thermal value, and a bi-stable relay;
closing the bi-stable relay;
holding open a first normally closed output terminal of a failsafe relay, an input terminal of the failsafe relay being connected to the battery positive terminal, wherein the first normally closed output terminal is connected to a first control input of the bi-stable relay operative to open the bi-stable relay;
and
in response to the first PTC component limiting current through the interruptible power circuit, deenergizing the failsafe relay, allowing the first normally closed output terminal to connect the battery positive terminal to the bi-stable relay first control input to open the bi-stable relay.

2 more elements

Dependencies are inferred from the claim text.

Dc power system breaker for transportation vehicle

Life of this patent

Dc power system breaker for transportation vehicle

Life of this patent

Abstract

Claims13