Functions, monitoring, and protective functions
9.3 Drive functions
Drive converter cabinet units
336
Operating Instructions, 07/07, A5E00288214A
9.3.13
Derating behavior at increased pulse frequency
Description
To reduce motor noise or to increase output frequency, the pulse frequency can be
increased relative to the factory setting.
The increase in the pulse frequency normally results in a reduction of the maximum output
current (see "Technical data/current derating depending on the pulse frequency").
When commissioning the converter the behavior at overload is adjusted in such a manner
that the pulse frequency is variably reduced so that the required power can be obtained.
Characteristics:
●
The reaction to overload depends on the setting of parameter p0290:
–
p0290 = 0: Reduce output current or output frequency
–
p0290 = 1: No reduction, shutdown when overload threshold is reached
–
p0290 = 2: Reduce the output current or output and pulse frequency (not using I²t).
–
p0290 = 3: Reduce the pulse frequency (not using I²t)
●
Bei p0290 = 2 at overload first reduce the pulse frequency until it has dropped to rated
pulse frequency, then reduce the output frequency if overload continues to persist.
●
Reduction of the pulse frequency is executed in whole multiples based on the rated pulse
frequency (5 kHz -> 2.5 kHz -> 1.25 kHz or 4 kHz -> 2 kHz).
●
After entering the maximum speed in p1082 the system automatically calculates whether
the pulse frequency is sufficient for the entered maximum speed, if necessary the pulse
frequency is increased automatically to a value that is necessary for this.
At overload, then also for p0290 = 2 or 3, this new pulse frequency will no longer be
underranged, the downstream reaction (reduce output voltage or switch off) will be
triggered.
Exceptions:
●
With an activated sinus filter (p0230 = 3, 4), this behavior is not permitted because the
factory set pulse frequency (2.5 kHz or 4 kHz) should not be changed through this
measure. Consequently in this case the selection possibility for the parameter p0290 is
limited to "0" and "1".
Activation of the variable pulse frequency
At commissioning the parameter p 0290 is automatically set to the value "2". This activates
pulse frequency reduction at overload.
Deactivation of the variable pulse frequency
By changing the parameter p0290 to "0" or "1" the variable pulse frequency is deactivated.
