| 摘要 |
PURPOSE:To save energy by stopping a spindle rotating with mechanical and electrical brakes, weakening the mechanical brake force during high-speed rotation, reducing thereby the wear of a brake shoe, and collecting the rotational energy during application of electric brakes. CONSTITUTION:When winding has attained a specific value, a switch 18a is turned off to shut off the current to a motor, and after passage of a set period of time, the contact 20b of a timer is put on to actuate an electromagnetic contactor 22b. Then the optimum voltage is supplied to the motor from commercial power supply via the contact of this contactor 22b, and the braking torque is applied to sink the speed as the motor is rotating at a speed in the power generating range, and the rotational energy is collected to the power supply. Meantime a relay 19a of the mechanical brake is turned off, and a traverse device actuates a limit switch 25, and during the electric brake in service a relay 19d is actuated to change over the passage in a solenoid valve 23a, so that a weak air pressure is fed to an air cylinder to press the brake shoe to the brake drum, when weak braking force is applied. |
