Patent ID: 8330400

Claim:
An electric motor drive system with a constant directional output transmission device, comprising: a bi-directional electric motor arranged to be driven in a forward direction and a reverse direction, wherein said electric motor directly or indirectly drives an input of the constant directional output transmission device; an electric motor control device for controlling at least a rotational direction and a speed or torque of the electric motor; an input device for issuing signals or commands to the electric motor control device to control said rotational direction and speed or torque; and at least a load wheel directly or indirectly driven in a constant direction by said constant directional output transmission device, and a current-detecting device for detecting a load current of the electric motor by detecting a voltage, electromagnetic induction, a magnetic field, or heat accumulation, said electric motor load current detecting device providing feedback to the electric motor control device, wherein a speed ratio of the constant directional output transmission device depends, at least in part, on a rotational direction of the electric motor, wherein when a load current of the electric motor exceeds a predetermined value for a predetermined time, the electric motor control device changes a rotational direction of said electric motor output to a rotating direction that provides an increased electric motor output speed and increased rotating speed or torque to said power input of said load, and wherein when the load current falls below said predetermined value, said electric motor is either manually controlled through the input device, or automatically controlled through the electric motor operative control device, to return to a normal status, including the original rotational direction and output power, to thereby enable the electric motor to be smoothly operated in the original rotational direction.