Patent ID: 8207700

Claim:
An AC or DC electric motor drive, comprising: safety switches determined by the safety of the electric motor drive, a controlled mechanical brake, as well as a power supply circuit of the brake control, a power converter having a network rectifier and a power rectifier of the motor, which power rectifier of the motor is at least partly implemented with controlled semiconductor switches arranged into a bridge, and an intermediate circuit between the network rectifier and the power rectifier of the motor, and a switch arrangement including two normally-open switches in the intermediate circuit of the power converter, of which a first switch is connected in series to the positive intermediate circuit busbar between the output of the network rectifier and the input of the power rectifier of the motor, and a second switch is connected in series to the negative intermediate circuit busbar between the output of the network rectifier and the input of the power rectifier of the motor, wherein the power rectifier of the motor includes: a quick-stop switch, and an amplifier circuit connected to the control pole of the controlled semiconductor switch, the electricity supply of which is arranged to occur via the aforementioned quick-stop switch, and wherein the semiconductor switches are fitted to switch into a conductive state when the amplifier circuit is in a controlled active state, and wherein the amplifier circuit supplied via the aforementioned quick-stop switch is fitted alternatively either in connection with the controlled semiconductor switches connected to the positive intermediate circuit busbar, in connection with the controlled semiconductor switches connected to the negative intermediate circuit busbar or in connection with the controlled semiconductor switches connected to both the positive and the negative intermediate circuit busbar.