Patent ID: 8138706
Filing Date: 2012-03-20
Classification: F24F,H02J

Abstract:
1. A safety drive having a safety circuit for returning into a predefined safety position a flap or a valve for controlling a gas volume flow or fluid volume flow, the safety drive comprising: an actuator drive with a controllable electric motor; a power feed for the electric motor; an intermediate circuit connecting the electric motor to the power feed; a capacitive energy store; and an energy converter connected to the intermediate circuit and being operable as a DC/DC converter having a step-down switching mode in which the energy converter receives as its input voltage a voltage of the intermediate circuit and in which the energy converter provides a reduced output voltage to the capacitive energy store, and being operable in a step-up switching mode in which the energy converter receives as its input voltage a voltage of the capacitive energy store, and in which the energy converter provides an increased output voltage to the intermediate circuit, the energy converter comprising a first controllable switch with a first diode which bypasses said first controllable switch, and comprising a second controllable switch with a second diode which bypasses said second controllable switch, the first controllable switch and the second controllable switch being connected in series within the energy converter, and wherein a series circuit composed of the capacitive energy store and an inductor is connected between a pole of the intermediate circuit and the connecting point of the first and second controllable switches, the energy converter forming a controllable power assembly which either charges the capacitive energy store from the power feed or discharges said capacitive energy store into the electric motor in order to operate the electric motor.