SIEMENS
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Siemens D 21.4 · 2017
Tools and configuration
Configuration notes
SINAMICS S120 Control Units
13
■
Configuration
(continued)
Influencing variables on minimum required pulse frequency of
power unit
Basic requirements such as maximum speed or necessary dy-
namic response of the control have a direct effect in determining
the minimum pulse frequency of the power unit. If the minimum
pulse frequency required exceeds the rated pulse frequency,
derating must be implemented accordingly
(see section
SINAMICS S120 drive system)
.
The following table provides a general overview.
Influencing variables
Minimum pulse frequency
Notes
Servo Control, Vector Control
(required max. output
frequency/speed)
100 Hz correspond to:
3000 rpm for
Z
p
= 2
1500 rpm for
Z
p
= 4
428 rpm for
Z
p
= 14
352 rpm for
Z
p
= 17
1.25 kHz
Z
p
is the number of pole pairs of the motor.
This equals 2 on 1PH asynchronous motors
(induction motors).
1FT7/1FK7 synchronous motors have
between 3 and 5 pairs of poles.
For torque motors, the numbers of pole
pairs are typically 14 and 17.
When edge modulation is used (only
possible for asynchronous motors), the
output frequency is increased by a factor
of 2.
160 Hz correspond to:
4800 rpm for
Z
p
= 2
2400 rpm for
Z
p
= 4
685 rpm for
Z
p
= 14
565 rpm for
Z
p
= 17
2 kHz
200 Hz correspond to:
6000 rpm for
Z
p
= 2
3000 rpm for
Z
p
= 4
856 rpm for
Z
p
= 14
704 rpm for
Z
p
= 17
2.5 kHz
300 Hz correspond to:
9000 rpm for
Z
p
= 2
4500 rpm for
Z
p
= 4
1284 rpm for
Z
p
= 14
1056 rpm for
Z
p
= 17
4 kHz
400 Hz correspond to:
12000 rpm for
Z
p
= 2
6000 rpm for
Z
p
= 4
4 kHz
Notice
: For Servo Control with 1FT7/1FK7
motors only.
Note field weakening requirements and
suitable encoder system for higher speeds.
V/f control
(required max. output
frequency/speed)
100 Hz correspond to:
6000 rpm for
Z
p
= 1
3000 rpm for
Z
p
= 2
1.25 kHz
V/f Control is only intended for induction
motors and SIEMOSYN motors.
Z
p
is the number of pole pairs of the motor.
This is mainly between 1 and 4 on 1LA/1LG
standard asynchronous motors (induction
motors).
SIEMOSYN motors have 1 or 2 pole pairs or,
with larger shaft heights, 3 pairs.
160 Hz correspond to:
9600 rpm for
Z
p
= 1
4800 rpm for
Z
p
= 2
2 kHz
200 Hz correspond to:
12000 rpm for
Z
p
= 1
6000 rpm for
Z
p
= 2
2.5 kHz
300 Hz correspond to:
18000 rpm for
Z
p
= 1
9000 rpm for
Z
p
= 2
4 kHz
400 Hz correspond to:
24000 rpm for
Z
p
= 1
12000 rpm for
Z
p
= 2
4 kHz
Dynamic response requirement
(current controller clock cycle)
125
μ
s
250
μ
s
400
μ
s
500
μ
s
4 kHz
2 kHz
2.5 kHz
1 kHz
Servo Control requires a minimum pulse
frequency of 2 kHz.
Sine-wave filters
–
4 kHz
Notice
: If sine-wave filters are operated at
low pulse frequencies, resonance problems
can occur and cause the filters to severely
overheat.
Output reactor to motor
Max. frequency: 150 Hz
correspond to 4500 rpm for
Z
p
= 2
The output reactor can be operated at
minimum 2 kHz only.
© Siemens AG 2017