DC motor series resistance starting circuit

A time relay is used to automatically control the two-stage series resistance starting control circuit of a separately excited DC motor . Its working principle is as follows:
    first close the switches QS2 and Qsl, the excitation windings Fl and F2 are excited by electricity. At the same time, the coils of the time relays KT1 and KT2 also
receive electricity at the same time, and their movable contacts are instantly disconnected. The coils of contactors KM2 and KM3 are de-energized, so
the moving and closing contacts KM2 and KM3 of the contactors connected in parallel to the starting resistors Ri and Rz are in the disconnected state, thus ensuring that the motor is connected to the armature circuit after all the starting resistors are connected in series. ,
the motor can start.
    Press the start button SBI, the contactor KM1 line is electrically activated, connects the armature circuit, and locks itself. The motor
starts under reduced pressure with all starting resistors connected in series . At the same time, due to the disconnection of the KM1 moving breaking contact, the time relay KT1 and KT2 coils are deenergized and delayed release.
After a certain delay time, the KT1 moving breaking contact is delayed to close first, and the contactor KM2 coil is energized. , its moving and closing contacts are closed,
short-circuiting the starting resistor RI, and then the moving-opening contacts of KT2 are closed in time to short-circuit the resistance island. The motor is started and put into normal operation.