Siemens MICROMASTER 440 Operating Instructions Manual page 214

3 Functions
Closed-loop Vector control without encoder (SLVC):
Starting from the initial value, the search frequency approaches the motor
frequency with the impressed current P1202. The motor frequency has been
found if both frequencies coincide. The search frequency is then kept constant
and the flux setpoint is changed to the rated flux with the magnetizing time
constant (dependent on P0346).
After the magnetizing time P0346 has expired, the ramp-function generator is set to
the speed actual value and the motor is operated with the actual reference
frequency.
f
Fig. 3-82
Flying restart with speed encoder
Depending on parameter P1200, after the de-magnetizing time P0347 expires
a) After the line supply returns with the automatic restart active, or
b) After the last shutdown using the OFF2 command (pulse inhibit)
flying restart is started with the maximum search frequency f
V/f characteristic (P1300 < 20):
For V/f control, the output voltage of the drive inverter is linearly increased from
0 to the V/f characteristic value within the magnetizing time P0347.
Closed-loop Vector control with speed encoder (VC):
For the closed-loop Vector control, the necessary magnetizing current is
established within the magnetizing time P0347.
After the magnetizing 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.
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 drives, with
low moments of inertia, to brake.
For group drives, "Flying restart" should not be activated due to the different
characteristics of the individual motors when coasting down.
WARNING
When "Flying restart" is activated (P1200 > 0), although the drive is at a stand-
still and the setpoint is 0, it is possible that the drive is accelerated as a result of
the search current !
If the operating range of the motors is entered when the drive is in this state,
this can result in death, severe injury or material damage.
214
f
search,max
Flying restart
Demagnetizing
P1202
time
P1203
P0347
Flying restart
Setpoint frequency
Magnetizing
Ramp up
time
P0346
search,max
MICROMASTER 440
Issue 10/06
t
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Operating Instructions
6SE6400-5AW00-0BP0