Patents by Inventor Roger L. Holman

Roger L. Holman 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).

  • Digital, Back EMF, single coil sampling, sensorless commutator system for a D.C. motor
    Patent number: 5672948
    Abstract: A digital, back EMF, single coil, sensorless up/down counter frequency adjustment system for a d.c. motor includes means for detecting the occurrence of a null voltage during the back EMF commutation state of a field coil; counter means for counting in one direction during the back EMF commutation state and for counting in the opposite direction when the null voltage is detected; means, responsive to the counter means, for ascertaining the final count of the counter means; and means, responsive to the means for ascertaining, for adjusting the frequency of initiation of the commutation states when a non-zero count is ascertained for synchronizing the field coil and the rotor.
    Type: Grant
    Filed: November 15, 1994
    Date of Patent: September 30, 1997
    Assignee: Cambridge Aeroflo, Inc.
    Inventors: Adam J. Cohen, Roger L. Holman, Rajesh M. Nair