DEVICE FOR REGULATION OF ROTATIONAL SPEED OF ELECTRIC MOTOR Russian patent published in 1998 - IPC

FIELD: control of electric motors, in particular, for manual electric appliances. SUBSTANCE: one claim of invention describes device design in which thyristor is connected in series with electric motor to mains line. In addition device has control resistor and capacitor which are connected to control electrode of thyristor through threshold gate. In addition device has controlled switching power supply which has capacitor unit of charge capacitors and gate units, and protection unit which is designed as non-symmetric flip-flop. Another claim of invention describes device design in which one resistor of divider of transistor collector potential in protection unit is designed as temperature-sensitive resistor. EFFECT: increased safety due to protection against thermal overload and spontaneous start after temporary loss of power supply voltage. 2 cl, 4 dwg