Flying Restart (Vector) - Siemens SINAMICS S120 Function Manual

4.16

Flying restart (vector)

Description
After power ON, the "flying restart" function switches automatically to a Motor
Module that may be coasting.
The "Flying restart" function should be activated via p1200 for an overrunning load.
This prevents sudden loads in the entire mechanics.
With an induction motor, the system waits for a demagnetization time to elapse
before the search is carried out. An internal demagnetization time is calculated.
A time can also be entered in p0347. The system waits for the longer of the two
times to elapse.
In operation without an encoder, a search is carried out initially for the current
speed. A Voltage Sensing Module (VSM) is required for permanent-magnet syn-
chronous motors for additional information, refer to the Equipment Manual.
For an induction motor, immediately after the speed has been determined, magne-
tization starts (p0346).
The current speed setpoint in the ramp-function generator is then set to the current
actual speed value.
The ramp-up to the final speed setpoint starts with this value.
Application example: After a power failure, a fan drive can be quickly reconnected
to the running fan motor by means of the flying restart function.
/
ON OFF command
ON
I
Absolute current
actual value
n
n
search,max
n
search
Demagnetize
n p1082 * 1.25
search,max
Fig. 4-13 Flying restart
© Siemens AG 2006 All Rights Reserved
SINAMICS S120 Function Manual, 03/2006 Edition
Find
Magnetize
Extended Functions
Flying restart (vector)
t
t
Setpoint speed
Ramp-up t
4-223