Ramanthan,

Can you take a high resolution (6400 lines) spectrum from, 0 to 120 orders and zoom in from 0 to 10 orders, and also zoom in on the data from, 90 to 120 orders and measure the sidebands, if any exists, in these 2 areas, not displaced in orders, but displayed in Hz?

Thanks,

Ralph

Thanks for for reply Mr. Ralph,

We found in the FFT 1X with pole pass frequency side band (amplitude 0.37  mm/sec RMS) in the motor and I zoomed the 90 to 120 order 2xRBPF frequency with 2 line frequency and found 675 cpm(0.375X )side band in the mentioned frequencies.

Thanks

RS

Ramanathan,

Thanks for the reply.

Based on the data you posted, quote: "We found in the FFT 1X with pole pass frequency side band (amplitude 0.37  mm/sec RMS) in the motor and I zoomed the 90 to 120 order 2xRBPF frequency with 2 line frequency and found 675 cpm(0.375X )side band in the mentioned frequencies." sounds like you may have a rotor with rotor bar problems, if the frequency of these "pole pass" sidebands you are referring to, are equal to the number of poles times the slip frequency of the motor?

Thanks,

Ralph