Patent attributes
The power-off electromagnetic brake (2) attracts an armature that is pressed by a spring force to a rotating member by a magnetic attraction force that is generated by energizing an exciting coil, and brake force that is acting on the rotating member is released. A voltage control circuit (12) continuously energizes the exciting coil for a fixed length of time and generates a considerable magnetic attraction force in order to attract the armature to a yoke when a brake power source (14) is switched on during brake release. After the armature has been attracted to the yoke, the voltage control circuit (12) intermittently energizes the exciting coil at a set cycle and a set on/off duty ratio to hold the armature in an attracted state to the yoke, thereby reducing power consumption and heat generation.
