| 摘要 |
PROBLEM TO BE SOLVED: To provide an emergency stop circuit which can realize a fail-safe function using a small and thin switch such as a sheet key. SOLUTION: At a normal time, a current from a current source 1 passes through a normally closed switch 2 and a parallel resistor 4 and operates a relay coil 6a and a relay contact 6b is turned under an on state. In the meantime, the current passes through a limit resistor 5 and operates a relay coil 7a and a relay contact 7b is turned under an ON state. Then, a power source 8 is connected with a motor 9, which is rotated. At the time of an emergency, a normally opened switch 3 is depressed and the parallel resistor 4 is short- circuited and more current flows to the relay coil 6a. Thus, a balance of the current distribution changes and the current which flows to the relay coil 7a becomes lower than a minimum driving current and the relay contact 7b is turned off. Also, when the normally closed switch 2 is depressed, the relay contact 6b is turned off and the motor 9 stops the rotation. COPYRIGHT: (C)2003,JPO
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