The second-order critical speed of the generator rotor and the first-order critical speed of the exciter rotor are close, and it is a three-support structure. The imbalance affects each other, and the vibration mode characteristics at the working speed are not obvious, making the analysis and judgment of the imbalance difficult. When the journal of the exciter No. 7 bearing bush is large, when there is a large second-order unbalance of the low-pressure rotor or the imbalance of the low-issue wheel, the imbalance of the rotor itself is affected, and the speed-increasing characteristics and working speed of the unit are affected. The lower characteristics are more complicated, and it is necessary to comprehensively analyze and judge the unbalanced position, so the balance difficulty is increased. The vibration treatment method of this type is: according to the phase characteristic relationship of the vibration amplitude under the working speed, the second-order critical speed of the generator and the first-order critical speed of the exciter, correctly analyze and judge the second-order unbalance and the third-order unbalance of the generator rotor. Balance and out-of-extension imbalance and first-order imbalance of the exciter rotor. Therefore, usually the No. 5 vibration is first considered for low-in-wheel balance or low-pressure rotor balance, followed by No. 5 watt-side generator rotor balance; No. 6, When the No. 7 vibration is large, the balance of the exciter rotor is firstly performed, mainly including the excitation of the wheel, the rectification ring and the end of the fan, and then the generator rotor balance on the 6th tile side.

Low-fabrication wheel connection short-axis bolt loosening occurred in our province. Two low-issue-to-wheel connection short-axis bolt loosening faults occurred in the start-up after overhaul. One time, the traditional manual tightening bolt was used in the overhaul to rely on the empirical method. Because the tightening force varies from person to person due to the uneven size, the main characteristic is that the shaft vibration of No. 4 is abnormal, the shaft amplitude value and the speed value of the abnormal vibration are related to the tightness of the bolt, and the difference between the shaft vibration and the vibration of the bridge Large, the main frequency of vibration is the power frequency, the vibration is mainly related to the speed, and the shaft vibration of No. 3 and No. 5 is small. This type of fault must be sufficient to eliminate the short-axis bolt tightening force of the low-fabrication wheel. Because this type of fault is difficult to judge, sometimes it is intended to solve the problem by low-pressure rotor dynamic balance, low-speed wheel alignment, etc., resulting in more detours and time.

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