Siemens SINAMICS G130 Engineering Manual page 25

The actual values depend on the PWM method used and the pulse frequency of the converter on the one hand, and
the design and number of poles of the motor on the other.
In the case of SINAMICS converters operating in vector control mode (drive object of vector type) at the factory-set
pulse frequency (1.25 kHz or 2.0 kHz), the increase in A-graded noise pressure level produced by the motor as a
result of the converter supply is typically within the 5 dB(A) to 10 dB(A) range.
The diagram below shows the scatter range of the increase in the A-graded noise pressure level ΔL
the motor in converter-fed operation as compared to operation directly on line at a 50 Hz supply system. This applies
to fin-cooled motors with 2, 4, 6 and 8 poles operating at the factory-set pulse frequency of 1.25 kHz or 2.0 kHz. The
values are lower for water-jacket-cooled motors and SIMOTICS TN series H-compact PLUS motors.
Increase in motor noise at operation on the factory-set
pulse frequency of 1.25 kHz or 2.0 kHz
Reduction in motor noise through increase in pulse frequency
By raising the pulse frequency, it is generally possible to lessen the increase in motor noise associated with
converter-fed operation. It must be noted, however, that raising the pulse frequency also necessitates inverter current
derating. Under certain boundary conditions (line voltage at low end of permissible wide-voltage range, low ambient
temperature, restricted speed range), it is possible to partially or completely avoid current derating at pulse
frequencies which are twice as high as the factory setting. For further information, please refer to section "Operation
of converters at increased pulse frequency". Increasing the pulse frequency not only necessitates current derating,
but might also impose limits on other motor-side options, such as motor reactors, dv/dt filters and sine-wave filters.
The diagram below shows the scatter range of the increase in the A-graded noise pressure level ΔL
the motor in converter-fed operation as compared to operation direcly on line at a 50 Hz - supply system. This applies
to fin-cooled motors with 2, 4, 6 and 8 poles operating at pulse frequencies of 2.5 kHz or 4.0 kHz which are higher
than the factory-set pulse frequencies. The values are lower for water-jacket-cooled motors and SIMOTICS TN series
H-compact PLUS motors.
Increase in motor noise at pulse frequencies of 2.5 kHz or 4.0 kHz (i.e. at higher than factory-set pulse frequencies)
Fundamental Principles and System Description
SINAMICS Engineering Manual – November 2015
Engineering Information
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