Selecting The Control Mode - Siemens Sinamics CU240D-2 DP Operating Instructions Manual

5.3.2

Selecting the control mode

Suitable applications and typical control properties
U/f control or FCC (flux current con-
trol) without an encoder
Application
Horizontal conveyor technology
•
examples
(conveyor belts, roller conveyors,
chain conveyors)
Pumps, fans, and compressors
•
with flow characteristic
Motors that
can be oper-
ated
The rated current of the motor must lie in the range of 13 % ... 100 % of the rated current of the inverter.
Properties of
Responds to speed changes with
•
closed-loop
a typical settling time of
motor control
100 ms ... 200 ms
Responds to load surges with a
•
typical settling time of 500 ms
U/f and FCC are suitable for the
•
following cases:
– For power-up times 0 → rated
speed > 2 s
– For applications with increas-
ing load torque without load
impulses
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 possi-
trol
Converter with the control units CU240D-2
Operating Instructions, 04/2018, FW V4.9 SP10, A5E34262100B AF
Induction motors
550 Hz
ble
Vector control without an encod-
er
Horizontal conveyor technol-
•
ogy (conveyor belts, roller
conveyors, chain conveyors)
Extruder
•
Centrifuges
•
Pumps and compressors with
•
displacement machines
Induction motors
Encoderless 1FK7 synchronous
motors
Reluctance motors
The vector control responds to speed changes with a typical
•
settling time of < 100 ms.
The vector control responds to load impulses with a typical
•
settling 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
•
accuracy of ± 5 % for 15
% ... 100 % of the rated
speed
Torque control for speeds >
15 % of the rated speed
Commissioning
5.3 Preparing for commissioning
Vector control with encoder
Vertical conveyor technolo-
•
gy (conveyor belts, roller
conveyors, chain convey-
ors)
Lifters/Lowerers
•
Stacker cranes
•
Induction motors
Extends the torque accura-
•
cy of ± 5 % to speeds
< 15 % of the rated speed.
240 Hz
Torque control from speeds = 0.
87