Linear drive unit, has brake that is parallel to DC motor brakes motor in generator operation, when voltage produced by motor exceeds preset value, and diode blocking current flow via brake, when motor is driven for raising load

摘要

The unit has a spindle driven by a DC motor (11), and an electrical brake (14) connected in parallel to the DC motor. The brake brakes the DC motor in a generator operation, when the voltage produced by the DC motor exceeds a predetermined value, which is adjustable. The brake exhibits a diode (15) that blocks the current flow via the brake, when the DC motor is driven for raising the load. A controller determines the voltage and opens a transistor, when the voltage exceeds a preset value so that the current flows into the brake via an electrical resistor.