Electric motor power connection assembly
View Patent ↗An electric motor power connection assembly diverts heat from an electrical conductor that carries electrical current between a power source and an electric motor. The electrical conductor is characterized by an effective cross-sectional area perpendicular to the direction of current flow and a length in the direction of current flow that is greater than the radius of a circle having the effective cross-sectional area. The “effective cross-sectional area” is the area perpendicular to the direction of current flow over which current is carried and thus depends on the cross-sectional shape and number of conductive components of the electrical conductor, which could be one or more wires. A heat diverting mechanism is positioned in thermal contact along the length of the electrical conductor to divert heat from the electrical conductor. The electric motor power connection assembly is suitable for use in a hybrid electro-mechanical transmission.
1. An apparatus comprising:
a power source;
a motor having a motor wire;
a power cable at least partially outside of the motor and operable to deliver current from the power source to the motor wire;
an electric motor power connection assembly operatively connecting the electric motor with the power cable and configured to allow the electric current to flow from the power cable to the motor wire; wherein the electric motor power connection assembly includes:
an electrical conductor for carrying the electric current through the assembly and characterized by an effective cross-sectional area through which the current is carried and a length in a direction of current flow; wherein the cross-sectional area is perpendicular to the direction of current flow;
a heat-diverting mechanism positioned in thermal contact along the length of the electrical conductor to divert heat from the electrical conductor; and wherein the length is greater than a radius of a circle having said cross-sectional area.
2. The apparatus of claim 1 , wherein the electrical conductor is an extended terminal; and wherein the heat-diverting mechanism is a cooling fluid applied along the length of the electrical conductor.
3. The apparatus of claim 2 , further comprising:
a motor terminal secured to the motor wire;
a threaded bolt sized to fit through the motor terminal and the extended terminal;
a threaded terminal block in which the bolt is secured; and wherein the bolt secures the extended terminal and the motor terminal to the threaded terminal block and in contact with one another to permit the current to flow therebetween.
4. The apparatus of claim 1 , further comprising:
an electrical insulator substantially enclosing the extended terminal along the length to define a passage therebetween; wherein the electrical insulator has an opening; and wherein the heat-diverting mechanism is pressurized fluid directed through the opening and through the passage to cool the extended terminal.
5. The apparatus of claim 1 , wherein the electrical conductor is an exposed portion of a power cable through which the current flows from the power source.
6. The apparatus of claim 1 , further comprising:
an electrical bus bar for supplying power to the power cable; and a thermally-conductive electrical insulator in thermal contact with the bus bar.
7. The apparatus of claim 1 , wherein the length is at least three times greater than the radius.
8. An electric motor power connection assembly for electrically connecting a motor with a power source to permit power flow to the motor, comprising:
an electrically conductive extended terminal for carrying electric current through the assembly and characterized by an effective cross-sectional area through which the current is carried and a length in a direction of current flow; wherein the effective cross-sectional area is perpendicular to the direction of current flow;
a cooling fluid applied over the length of the extended terminal to divert heat from the extended terminal; wherein the length is greater than a radius of a circle having said effective cross-sectional area;
a power cable through which the current flows;
a bus bar in operative electrical contact with the power cable for supplying the current to the power cable;
a thermally-conductive electrical insulator in thermal contact with the bus bar; and
a heat sink in thermal contact with the thermally-conductive electrical insulator.
9. The electric motor power connection assembly of claim 8 , further comprising:
a motor wire operatively connected to the motor for providing the current thereto;
a motor terminal secured to the motor wire;
a threaded bolt sized to fit through the motor terminal and the extended terminal;
a threaded terminal block through which the bolt is secured; and wherein the bolt secures the extended terminal, the motor terminal and the threaded terminal block together and in contact with one another to permit the current to flow between the extended terminal and the motor terminal.
10. A hybrid transmission comprising:
a transmission casing defining a transmission cavity;
a power source located outside of the transmission cavity;
an electric motor located in the transmission cavity for powering the transmission; wherein the electric motor is operatively connected to the power source and powered by electric current derived from the power source;
a motor wire operatively connected to the electric motor for providing the electric current thereto;
an electrical conductor operatively connected between the power source and the motor wire for carrying the electric current therebetween and characterized by an effective cross-sectional area through which the current is carried and a length in a direction of current flow; wherein the effective cross-sectional area is perpendicular to the direction of current flow;
a heat-diverting mechanism positioned in thermal contact along the length of the electrical conductor to divert heat from the electrical conductor along the length; and wherein the length is greater than a radius of a circle having said effective cross-sectional area.
11. The hybrid transmission of claim 10 , wherein the length is at least three times greater than the radius.
12. The hybrid transmission of claim 10 , further comprising:
a power cable carrying the electric current from the power source to the electrical conductor; wherein the electrical conductor is a bus bar for supplying electric current to the power cable; wherein the heat-diverting mechanism is a thermally-conductive electrical insulator in thermal contact with the bus bar; and
a heat sink in thermal contact with the thermally-conductive electrical insulator.
13. The hybrid transmission of claim 10 , further comprising:
a power cable carrying the electric current between the power source and the motor wire; and wherein the power cable is characterized by an overall length in the direction of current flow and a power cable effective cross-sectional area; and wherein the overall length is not greater than one thousand times a radius of a circle having said power cable effective cross-sectional area.
14. The hybrid transmission of claim 10 , further comprising:
a power cable carrying the electric current from the power source to the electric conductor; wherein the electrical conductor is an extended terminal secured to the power cable; and wherein the heat-diverting mechanism is a cooling fluid applied over the length of the electrical conductor.
15. The hybrid transmission of claim 10 , further comprising:
a power cable carrying the electric current from the power source to the electric conductor; wherein the electrical conductor is an extended terminal secured to the power cable;
an electrical insulator substantially enclosing the extended terminal along the length to define a passage therebetween; wherein the electrical insulator has an opening; and wherein the heat-diverting mechanism is pressurized fluid directed through the opening and through the passage to cool the extended terminal.
16. The hybrid transmission of claim 10 , wherein the electrical conductor is a power cable through which the current flows from the power source; wherein the power cable has an exposed portion; and wherein the length is the exposed portion of the power cable.