To determine whether the motor and the ZSY224-35.5-2 hardened cylindrical gear reducer require mechanical balance correction, a comprehensive judgment must be made based on equipment operating data, vibration characteristics, component status and other dimensions. The following are 3 core judgment criteria, each of which includes specific judgment standards, detection methods and practical details, which can be directly used for on-site inspection:
1. Quantitative judgment based on vibration data (core basis)
Use a vibration analyzer to detect the vibration values of key parts of the equipment, focusing on vibration speed (RMS) and vibration frequency characteristics, and determine the threshold based on national standards and equipment manuals:
Detection position and standard threshold:
Motor bearing end: vibration speed ≤2.8mm/s (RMS) (GB/T 10068-2020 standard, G2.5 grade motor requirements);
Reducer box body (input end, output end bearing seat): vibration speed ≤ 4.5mm/s (RMS) (general standard for industrial gearboxes);
Reducer output shaft end: vibration speed ≤5.0mm/s (RMS) (considering the large torque characteristics of ZSY224-35.5-2, the threshold can be moderately relaxed).
Frequency feature determination:
If the dominant frequency of vibration is the motor speed frequency (n/60, n is the rated speed of the motor, such as 25Hz at 1500r/min) or the speed frequency of the reducer shaft system (input shaft = motor speed, output shaft = motor speed/35.5), and the vibration amplitude at this frequency accounts for more than 60% of the total vibration, it means that the vibration is dominated by the imbalance of the rotor/shaft system, and balance correction is required;
Example: When the motor runs at 1500r/min, if the vibration speed corresponding to the 25Hz frequency is ≥3.5mm/s (RMS), and after excluding factors such as coaxiality deviation and bearing failure, it can be determined that the motor rotor needs balance correction; the speed of the reducer output shaft ≈42.25r/min (frequency ≈0.7Hz). If the vibration amplitude at this frequency continues to exceed the standard, the balance status of the output shaft and gear shaft needs to be checked.
Detection method:
Use a portable vibration analyzer (such as a vibration measuring pen, CSI 2140), select the 'Speed Effective Value (RMS)' measurement mode, test the equipment under no-load and rated load conditions, and take the average of 3 measurements;
If the vibration value under load conditions increases by ≥50% compared with the no-load condition, and the dominant frequency is the shaft system speed frequency, priority should be given to troubleshooting the imbalance problem (rather than load impact).
2. Qualitative judgment based on operating characteristics and abnormal noise
By observing the operating status of the equipment on site, listening to abnormal noises, and judging by the periodic characteristics of vibration:
Vibration periodicity and stability:
The vibration increases linearly as the rotational speed increases (for example, the motor increases from 1000r/min to 1500r/min, the vibration speed increases from 2.0mm/s to more than 4.0mm/s), and there is no obvious impact peak. It is most likely that the rotor/shafting system is unbalanced (unbalanced vibration is proportional to the square of the rotational speed);
The vibration has no obvious speed correlation and is accompanied by impact peaks. Problems such as gear meshing faults and bearing damage need to be eliminated first before considering balance.
