PURPOSE: To discriminate a pulse disk where an error is being generated at the time of beginning to run, by detecting the speed of the fastest wheel and emitting an alarm signal or a cut-off signal to a control device when a period, when a ratio of the speed of the fastest wheel to the speed of a wheel located at the same side exceeds an limiting value, reaches a prescribed percentage.
CONSTITUTION: A period T necessary for the acceleration of the slowest wheel from a lower limiting value Vu to an upper limiting value Vo is measured by a counter 12. At the same time, when a ratio of the speed of the fastest wheel to the speed of a wheel located at the same side is between fmin and fmax, an error is generated and a period T' for discriminating the error is measured by a counter 19. Monitoring the speed of the slowest wheel Vmin is ended when it exceeds the upper limiting speed Vo, and then, the time counters 12 and 19 are analyzed. If the error continues during at least 75% of the monitor period, there is a possibility that the fastest wheel is a wheel with a pulse disk where the error is generated. In this case, an error signal 22 is generated.
BUIRUFURIITO ENDERURE
KURAUSUUPEETAA MATSUTERUN
