When the electric motor is supplied with current, the stator armature winding of the motor generates a rotating magnetic field. There is relative motion between the rotating magnetic field and the stationary rotor, causing the magnetic lines of force from the rotating field to cut through the rotor conductors, thereby inducing current in the rotor conductors. This current interacts with the rotating magnetic field to produce electromagnetic force, creating an electromagnetic torque on the rotor shaft that causes the rotor to rotate. The rotor then drives the engine crankshaft via the drive mechanism, starting the vehicle. Cigarette lighter output: An alternative to jumper cables is a cable that connects the 12-volt power outputs (cigarette lighter outputs) of two vehicles. While this eliminates concerns about incorrect connections and arcing near the battery terminals, the amount of current that can be obtained through this connection is very small. This method works by slowly recharging the battery rather than providing the current needed for starting. Charger: Driving and service garages typically have portable battery chargers based on mains electricity. Very small "trickle" chargers are designed only to maintain the charge on parked or stored vehicles, but larger chargers can store enough charge in the battery to allow starting within minutes. Battery chargers can be fully manual or include controls for time and charging voltage.
