| 摘要 |
<p>PURPOSE:To protect an electric motor coach even if the direction of a start command is in error by comparing the direction of the start command of the coach with the rotating direction of a rotor of an induction motor and stopping a variable voltage/variable frequency inverter which drives a motor when both directions are different to each other. CONSTITUTION:A DC current collected by a pantograph 1 drives an induction motor 3 through a variable voltage/variable frequency inverter 2. A pulse sensor 6 is mounted on the rotor of the motor 3 to detect a signal of the rotating direction according to which of pulse elements 6a, 6b provided, for example, so that the distances therefrom to the center of rotation are different passes earlier through the detecting point. A controller 7 inputs a power drive or a brake command, forward or reverse drive command and a frequency fM from the sensor 6 and instructs so that the inverter 2 produces output voltages in the prescribed sequence of phases corresponding to the command. A comparator 8 compares the direction of the command with the rotating direction of the rotor to produce a signal for stopping the inverter 2 when different. In this manner, an electric motor coach can be protected.</p> |
