| 摘要 |
PURPOSE:To remarkably shorten the allover braking time of a synchronous machine from the initial of braking to the stoppage by using an electricbrake with an external resistor at the initial time of braking and switching to an eletric brake in which 3-phase are short-circuited directly at the time when the braking force is decreased with the decrease of the revolution. CONSTITUTION:After a generator 1 is disconnected from a system, a disconnecting switch 2 is closed without excitation, and an electric brake is engaged with a switch 4 retained open. An armature current flows into an external resistor 3, the rotating energy of the generator 1 is consumed by the copper loss of the resistor 3, and a large braking force can be obtained in a high speed zone. When the switch 4 is closed when the revolution of the generator 1 is decreased to a certain speed and the resistor 3 is short-circuited, it becomes an electric brake in which 3-phases are short-circuited directly, the rotating energy of the generator 1 is consumed by the copper loss of the armature winding, and a large braking force can be obtained in a low speed zone. |
