Patents by Inventor Peter John Lawrenson

Peter John Lawrenson has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Electric stepper motors
    Patent number: 4100473
    Abstract: An electric stepper motor has in addition to the usual driving coils at least one additional coil wound on its stator and connected in a closed circuit. This additional coil damps any oscillations of the rotor. The closed circuit has a resistive value optimized to achieve maximum damping effect. Two or more such additional coils may be connected in a single closed circuit and a number of such closed circuits may be provided.
    Type: Grant
    Filed: September 30, 1976
    Date of Patent: July 11, 1978
    Assignee: National Research Development Corporation
    Inventors: Peter John Lawrenson, Austin Hughes
  • Electric stepper motors
    Patent number: 4044291
    Abstract: A stepper motor has impedance in series with each drive coil and the value of the impedance is changed during each drive pulse. Two different paths for current to a drive coil may be provided each having a different value of impedance and the current to the drive coil is switched between the two paths during each drive period.
    Type: Grant
    Filed: September 23, 1975
    Date of Patent: August 23, 1977
    Assignee: National Research Development Corporation
    Inventors: Austin Hughes, Peter John Lawrenson