| 摘要 |
In a lift d.c. motor drive arrangement an alternating supply current (Us) is rectified in a manner known in itself in prior art. In order to eliminate the drawbacks of conventional four-quadrant thyristor bridges, the d.c. voltage that is formed is conducted to an energy storage battery (2) supplying the main drive energy for the d.c. motor (3), and the drive voltage (Uz) for the d.c. motor (3) is formed from the constant, or intermediate, voltage (Uv) of the energy storage (2) by pulse-width modulating it by means of switching elements (4,5,6,7), known in themselves in prior art, which enable the motor (3) to be controlled in four quadrants. <IMAGE> |
