中科微点-全球专利检索

  1. Login
  2. Sign Up

Search Results

7 records (took 0.01 seconds)

    Variable frequency motor drive
    2.
    发明授权
    Variable frequency motor drive 失效
    可变频率电机驱动

    公开(公告)号：US3588650A

    公开(公告)日：1971-06-28

    申请号：US3588650D

    申请日：1969-09-05

    Applicant: CHALCO ENG CORP

    Inventor： BEVIS JEFFREY M

    IPC: H02P27/06 ,  H02P5/40

    CPC classification number: H02P27/06 ,  H02P27/047 ,  H02P2201/03

    Abstract: THE SPEED OF AN AC MOTOR CAN BE CONTROLLED BY VARYING THE INPUT FREQUENCY AND VOLTAGE SUPPLIED TO THE MOTOR. THE INVENTION IS CHARACTERIZED BY A SOLID-STATE SWITCH BRIDGE CONNECTED TO THE ELECTRIC MOTOR FOR SUPPLYING GENERALLY SQUARE WAVE VOLTAGE PULSES TO THE MOTOR AT THE DESIRED FREQUENCY. THE SQUARE VOLTAGE PULSES ARE CHOPPED TO ADJUST THE AVERAGE VOLTAGE SUPPLIED TO THE MOTOR TO MAINTAIN THE CONSTANT TORQUE CHARACTERISTIC REQUIRED FOR THE INPUT FREQUENCY TO THE MOTOR. AN RC ATTENUATING CIRCUIT IS CONNECTED TO THE MOTOR IN SUCH A WAY THAT WHEN THE FREQUENCY IS CHANGED THE REGULATED LEVEL OF THE AVERAGE MOTOR VOLTAGE IS AUTOMATICALLY CHANGED TO A VALUE WHICH MAINTAINS THE TORQUE IN THE MOTOR SUBSTANTIALLY CONSTANT.

    Magnetic brake
    3.
    发明授权
    Magnetic brake 失效
    MAGNETIC BRAKE

    公开(公告)号：US3624358A

    公开(公告)日：1971-11-30

    申请号：US3624358D

    申请日：1967-05-29

    Applicant: CHALCO ENG CORP

    Inventor： BEVIS JEFFREY M

    IPC: G06K13/22 ,  G06K13/26 ,  G11B15/22 ,  B65H25/32 ,  G06K7/08 ,  G11B5/40

    CPC classification number: G06K13/22 ,  G06K13/26

    Abstract: In order to achieve the high speed brake operation required for use in tape readers, without producing an accompanying objectionable high heat loss requiring auxiliary cooling systems for the tape reader, an induction coil having an inductance much higher than the inductance of the coils in the magnetic brakes is connected in series with a transistor and a constant current generator. One end of the brake coil is connected to the junction between the induction coil and a transistor. The brake coils are in series with a second transistor and the brake coils and the second transistor are in parallel with the first transistor. Appropriate circuitry is provided for causing the first transistor to become conductive while the second transistor becomes nonconductive and means are provided for causing these transistors to change their mode each time an appropriate pulse is applied to the circuitry. When the first transistor becomes nonconductive, interruption of the current in the induction coil produces a large voltage at the junction of the inductance coil and the first transistor. This high voltage rise is very rapid because of the rapid interruption of the current in the coil (L di/dt). Consequently, the high voltage connected across the brake coils abruptly actuates them. When a brake off pulse is applied to the circuitry, the second transistor becomes nonconductive and the first transistor becomes conductive. This in turn causes the energy in the brake coils to discharge through the second transistor.

Patent Agency Ranking