Turning brake controlling system for use in power shovel

A turning brake controlling system for use in an upper turning body of a power shovel, comprising:

• a microprocessor means for receiving a turning lever signal from a turning lever signal transmitter when a turning lever is shifted from a turning portion to a neutral position thereof, and for transmitting a turning brake actuating signal to the turning brake actuator means;
• a microprocessor monitoring means operably connected to said microprocessor means for monitoring an operation of said microprocessor means;
• a hardware circuit means connected in parallel with said microprocessor means for performing arithmetic functions of said microprocessor means;
• and
• a switching circuit means for switching output of said microprocessor means over to an output of said hardware circuit means in accordance with the actuation of said microprocessor monitoring means, wherein at least one of said microprocessor means and hardware circuit means includes a turning speed detector means for detecting a turning speed of said upper turning body when said turning lever is shifted from said turning position to said neutral position thereof and subsequent speeds thereof, and for outputting a turning speed signal corresponding to a detected turning speed;
• and a turning brake signal generator means for receiving said turning speed signal outputted by said turning speed detector means and said turning lever signal outputted by said turning lever signal transmitter means and for outputting a turning brake signal to said turning brake actuator means, and wherein said turning brake signal generator means is arranged to output a turning brake signal in a delay time which is present in accordance with the value of said turning speed signal.