Prohibited Frequencies (M3.7) - Siemens bt300 Operator's Manual

Prohibited Frequencies (M3.7)

In some systems it may be necessary to avoid certain frequencies due to mechanical resonance problems. By
setting up prohibited frequencies, these ranges are skipped.
The prohibited frequencies settings are presented in the following table:
Structure Parameter
P3.7.1 Range 1 Low Lim
P3.7.2 Range 1 High Lim
P3.7.3 Range 2 Low Lim
P3.7.4 Range 2 High Lim
P3.7.5 Range 3 Low Lim
P3.7.6 Range 3 High Lim
P3.7.7 RampTimeFactor
Siemens Industry, Inc.
Building Technologies
Table 44: Prohibited Frequencies Settings.
Unit Min
Hz 0 320
Hz 0 320
Hz 0 320
Hz 0 320
Hz 0 320
Hz 0 320
0.1 10
Example:
A resonance noise is occurring on an air handling unit when the drive speed is around
75% (45 Hz). Complete the following:
1. Set Prohibited Frequency Range 1 Low Limit (P3.7.1) to a value of 44.5.
2. Set Prohibited Frequency Range 1 High Limit (P3.7.2) to a value of 45.5.
Siemens BT300 HVAC Drive
Chapter 4 - Parameters and Menu Structure
Max Default ID
0 509
0 510
0 511
0 512
0 513
0 514
1 518
Parameters (M3)
Description
Defines the low limit of the first
prohibited frequency. The drive will
change its accel/decel time by the
RampTimeFactor (P3.7.7) while
within the range of this low limit and
the Range 1 High Lim (P3.7.2).
NOTE: The drive will not control
within these ranges, it will either be
faster or slower, but never within
the range defined.
Defines the high limit of the first
prohibited frequency. The drive will
change its accel/decel time by the
RampTimeFactor (P3.7.7) while
within the range of this high limit
and the Range 1 Low Lim (P3.7.1).
NOTE: The drive will not control
within these ranges; it will either be
faster or slower, but never within
the range defined.
Defines the low limit of the second
prohibited frequency. See Range 1
Low Lim (P3.7.1) for further details.
Defines the high limit of the second
prohibited frequency. See Range 1
High Lim (P3.7.2) for further details.
Defines the low limit of the third
prohibited frequency. See Range 1
Low Lim (P3.7.1) for further details.
Defines the high limit of the third
prohibited frequency. See Range 1
High Lim (P3.7.2) for further details.
Defines the multiplier of the
currently selected ramp time (accel
time 1/2 and decel time 1/2)
between the prohibited frequency
limits.
DPD01809
2016-06-07
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