Patent ID: 8874294

Claim:
A trolley assist-capable electric drive truck comprising: a frame; a plurality of ground engaging elements coupled to the frame; an onboard electrical power source attached to the frame and including an internal combustion engine mechanically coupled to an electrical power generator; at least one electric propulsion motor coupled to the ground engaging elements; a circuit electrically connecting the electrical power generator to the electric propulsion motor; a pantograph supported on the frame and movable between a trolley line engagement configuration and a stowed configuration; a DC link that electrically connects the circuit to the pantograph, and including a first contactor electrically separating a positive direct current conductor from a positive pantograph conductor; a second contactor electrically separating a negative direct current conductor from a negative pantograph conductor; the positive direct current conductor being electrically separated from the negative direct current conductor by the first contactor, a third contactor, a grid resistor and the second contactor; and each of the first, second and third contactors being changeable between an open circuit configuration and a closed circuit configuration.