Pulsewidth speed regulating and electric brake of DC motor

The utility model discloses a pulse-width speed regulating and electric braking device of DC motor, mainly applied in the electric drive field of speed regulating and electric braking of DC motor. The device comprises a motor rotor winding (4) and an excitation winding (10), a power device (11), a DC contactor (3), a DC switch (1), a condenser (2) and three diodes, two resistors, etc. The utility model is characterized in that the diodes (7) are connected between the motor rotor winding and the excitation winding, etc. The utility model, through controlling the on and off of the DC switch (1) and the DC contactor (3), determines the motor positions in the speed governing state or the electric braking state; through controlling the pulse-width of the power device (11), regulates the operating speed of the motor or the size of the brake force; the utility model is an electric control device of stably governing speed and combining with non-contact electric braking. The utility model is suitable for the situations which needs stably govern speed or frequently brake of electric bicycle, trolley bus, the assembly line of conveying belt and mechanical device, etc.