Yaskawa J7 Drive - Manual (Page 41)

5-6
A. n49 : Prohibited Frequency 1 Factory setting (each): 0.0
n50 : Prohibited Frequency 2
Range (each): 0.0 to 400 Hz
These parameters allow programming of up to three prohibited frequency points for eliminating
problems with resonant vibration of the motor/machine. This feature does not actually eliminate the
selected frequency values, but will accelerate and decelerate the motor through the prohibited
bandwidth.
B. n51 :
Prohibited Frequency Deadband Factory setting:
0.0
Range: 0.0 to 25.5 Hz
This parameter determines the width of the deadband around each selected prohibited frequency
point. The factory setting is " 1.0 ", which establishes a deadband of ±1.0 Hz.
EXAMPLE:
Vibration encountered between 30.0 and 36.0 Hz.
SOLUTION:
Set n49 to " 33.0 ". This is the center of the problem
frequency band.
Set n51 to " 3.0 ". This will cause the Drive to reject all
frequency command values between 30.0 and 36.0 Hz.
A frequency command in the deadband will be converted to the bottom
value of the deadband, e.g. a command of 33 Hz would result in a run
frequency of 30 Hz.
NOTE: n49 > n50 - The highest prohibit frequency required needs to be in n49 and the
lowest prohibit frequency needs to be in n50 .
FREQ. CMD
36 Hz
n49 = 33 Hz
30 Hz
0
Total Deadband = 6.0 Hz
± n51 (3.0 Hz)
OUTPUT FREQUENCY (Hz)
5.6 CRITICAL FREQUENCY REJECTION