Siemens SINAMICS G120 Operating Instructions Manual page 294

Functions
8.17 Flying restart
Flying restart with speed encoder
Depending on parameter P1200, after the demagnetization time P0347 expires, the flying
restart is started with the maximum search frequency fsearch,max.
1. After the line supply returns with the automatic restart active
2. After the last shutdown using the OFF2 command (pulse inhibit)
● V/f characteristic (P1300 < 20):
● Closed-loop Vector control with speed encoder (VC):
After the magnetization time P0346 has expired, the ramp-function generator is set to the
speed actual value and the motor is operated at the actual setpoint frequency.
Warning
When "Flying restart" is activated (P1200 > 0), although the motor is at a standstill and the
setpoint is 0, it is possible that the motor can be accelerated as a result of the search
current!
If the operating range of the motor is entered when the motor is in this state, this can result in
death, severe injury or material damage.
Note
If a higher value is entered for the search velocity P1203 this results in a flatter search curve
and therefore to an extended search time. A lower value has the opposite effect.
For "Flying restart", a braking torque is generated which can cause motors, with low
moments of inertia, to brake.
For group motors, "Flying restart" should not be activated due to the different characteristics
of the individual motors when coasting down.
8-98
For V/f control, the output voltage of the inverter is linearly increased from 0 to the V/f
characteristic value within the magnetization time P0346.
For the closed-loop Vector control, the necessary magnetization current is established
within the magnetization time P0346.
Operating Instructions, 11/2006, A5E00766042B AA
Control Units CU240S