Method for assessing a rotational speed of an engine
AssigneeSchneider Electric Industries SAS
InventorsDavid R Brown, Shuai Wu, Gerard Gomez
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Abstract
A method assesses the rotational speed of a machine, and more particularly the rotational speed of a rotating equipment prime mover controlled by a governor. Such machines include turbo machinery and relate to a measurement device for measuring speed. The method measures a number of pulses during a measurement interval, determines a portion of a pulse pattern, determines an integration period, and calculates the rotational speed based on the portion of the pulse pattern.
Claims14
A method for assessing a rotational speed of an engine, comprising:
- measuring a number of pulses during a measurement interval;
- providing at least one stored pulse pattern;
- determining a portion of the stored pulse pattern by comparing the measured pulses against the stored pulse pattern, and selecting the portion of the stored pulse pattern that matches the measured pulses;
- determining an integration period;
- and
- calculating the rotational speed based on the determined portion of the stored pulse pattern.
A measurement device for measuring a rotational speed of an engine, comprising:
- a system clock providing a system clock signal;
- a time base generator determining a sampling period derived from the system clock signal;
- a counter clock providing a counter clock signal derived from the system clock signal;
- an input pulse counter counting pulses of the input signal during sampling period and keeping track of an index of the input pulses;
- a time counter counting pulses of the counter clock between two consecutive pulses of the input signal;
- and
- a latching memory for capturing and storing the index of a value of the input pulse counter and a value of the time counter at an end of the sampling period of both a current sample period and a previous sample period.
Dependencies are inferred from the claim text.