Siemens SINAMICS G120D Operating Instructions Manual page 83

U/f control or FCC (flux current con‐
trol) without an encoder
Properties
• Responds to speed changes with a
of closed-
typical settling time of
loop motor
100 ms ... 200 ms
control
• Responds to load surges with a typ‐
ical settling time of 500 ms
• U/f and FCC are suitable for the fol‐
lowing cases:
– For power-up times 0 → rated
speed > 2 s
– For applications with increasing
load torque without load impul‐
ses
• The closed-loop control is insensi‐
tive to inaccurate motor data set‐
tings, e.g. the motor temperature
Max. output
frequency
Torque con‐ Closed-loop torque control not possible Torque control for speeds > 15 %
trol
Converter with the control units CU240D-2
Operating Instructions, 10/2020, FW V4.7 SP13, A5E34262100B AH
•
•
•
•
550 Hz
Vector control without an en‐
coder
The vector control responds to speed changes with a typical set‐
tling time of < 100 ms.
The vector control responds to load impulses with a typical set‐
tling time of 200 ms.
The vector control is required in the following cases:
– For power-up times 0 → rated speed < 2 s
– For applications with fast and high load impulses
Typically achieves a torque ac‐
curacy of ± 5 % for 15 % ...
100 % of the rated speed
of the rated speed
Commissioning
5.3 Preparing for commissioning
Vector control with encoder
• Extends the torque accuracy
of ± 5 % to speeds < 15 % of
the rated speed.
240 Hz
Torque control from speeds = 0.
81