Rockwell Automation 20A PowerFlex 70EC/700VC - Manual (Page 61)

Notch Filter 57
Important: If the application requires high overload current for long durations
(e.g. 150% for 60 seconds), heavy duty sizing (between drive and
motor) will be required. See "Normal Duty and Heavy Duty
Operation" on
page 39 .
Notch Filter A notch filter exists in the torque reference loop to reduce mechanical resonance
created by a gear train. [Notch Filter Freq] sets the center frequency for the 2 pole
notch filter, and [Notch Filter K] sets the gain.
Figure 9 Notch Filter Frequency
Example
A mechanical gear train consists of two masses (the motor and the load) and spring (mechanical
coupling between the two loads). See
Figure 10 .
Figure 10 Mechanical Gear Train
The resonant frequency is defined by the following equation:
Figure 11 shows a two mass system with a resonant frequency of 62 radians/second
(9.87 Hz). One Hertz is equal to 2
π radians/second.
70EC 700VC 700H
✔
Gain
0 db
Hz Notch Filter Frequency
Notch Filter K
Kspring
BL Bm
Jm Jload
Jm is the motor inertia (seconds)
Jload is the load inertia (seconds)
Kspring is the coupling spring constant (rad
2 /sec)
resonance Kspring
Jm Jload +
( )
Jm Jload
Ч
------------------------------- =