Digital wheel speed circuit arranged to compensate for dimensional irregularities of sensor rotor member Patent #: 4050747
ApplicationNo. 06/258926 filed on 04/30/1981
US Classes:377/28, Identifying or correcting improper counter operation (e.g., error checking, monitoring; preventing or correcting improper counter operation)324/76.47, Digital output324/76.55, Digital output324/76.77, Phase comparison (e.g., between cyclic pulse voltage and sinusoidal current, etc.)377/39, Comparing counts377/43Having phase shift
ExaminersPrimary: Orsino, Joseph A.
Assistant: Greer, Timothy K.
Attorney, Agent or Firm
International ClassH02H 3/46 (20060101)
Foreign Application Priority Data1980-04-30 JP
AbstractA digital frequency relay for use in protecting an electrical power transmission line in the event of frequency deviations indicative of a fault condition, including an input device for receiving AC electric signals, and an oscillator for generating a reference frequency, which are connected to respective first and second counters which respectively count the number of output pulses from the oscillator during the AC electric signal positive half-cycle, and during the AC electric signal negative half-cycle. The resultant output from the first and second counters is added and compared with a set value to produce a trip signal for the frequency relay.
Field of SearchVoltage