JPS5571186A - Safety gear - Google Patents

Abstract

PURPOSE: To prevent unstable functioning in speeding and low-speed ranges that exceed the prearranged maximum speed of a motor, by suspending the supply of power to the motor wherein the motor is let respond to abnormal signsls generated in the case when speed instruction signals deviate from a set range.

CONSTITUTION: When the output of a speed instruction means 10 reaches a high level by the disconnection of a connecting wire 6, a signal 0 is put out because the relationship that the numerical value A of signals emitted at an upper limit value set instrument 24 is larger than the numerical value B of signals issued at an AD converter 9 is not formed in a discriminator 23, and a signal 1 is put out because the relationship that A is smaller than B is organized in a discriminator 22. Thus, the signal 1 is put out from an OR circuit 26, converted into 0 by means of an inverter 42 and input to a RT terminal of a flip-flop circuit 43. The flip-flop circuit 43 continuously maintains a set condition by SN signals because a one-shot mutivibrator 41 is not triggered even if the signal 1 of the OR circuit 26 is input, and the supply of power to a motor 100 is intercepted.

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