TB-20AThe TB-20A dynamic balancing measuring instrument is applied to high and medium speed rotating bodies such as turbogenerators, turbo compressors, various centrifuges, fans, pumps, etc., and low-speed rotating parts such as water turbines and rollers. When the mass center does not coincide with the rotation center due to various reasons, vibration is generated by centrifugal force. This instrument is multifunctional; it can be used as a tachometer, as well as for vibration testing and analysis, especially with all functions for measuring dynamic balance.
Several Issues in Dynamic Balancing Measurement
7.1, Confirm whether the rotor equipment has vibration caused by unbalance
First, confirm whether the rotor equipment has vibration caused by unbalance. The vibration of field equipment is complex, generally mixed-frequency vibration. Only when the unbalanced vibration component accounts for more than 80% of the total mixed-frequency vibration, can this instrument show its effect. Specifically, use the "FFT analysis" function in the "Signal Analysis" of this instrument to perform spectrum analysis on the vibration signal. Through spectrum analysis, if the vibration at the fundamental frequency is large, and the vibration at other multiples is very small or even absent, then using this instrument can achieve satisfactory results. Compare the vibration value in vibration measurement with that in dynamic balancing measurement. When the vibration value in dynamic balancing measurement is close to that in vibration measurement, it is considered that the unbalance value accounts for a large percentage of the total vibration value, and the dynamic balancing measurement effect is obvious. Otherwise, the measurement effect may be unsatisfactory.
7.2, Basic requirements of the dynamic balancing instrument for equipment
Basic requirements of the dynamic balancing instrument for machinery and equipment:
①Within the working speed range, it can be started and stopped multiple times. Specifically, using the trial weight method, for single-plane balancing, at least 3 starts are required, and for double-plane balancing, at least 4 starts are required to see the effect of dynamic balancing.
②It is convenient to add or remove weight on the rotor on site. For any enclosed rotating rotor or shaft system, or where adding or removing weight on the rotor correction plane is not allowed, dynamic balancing operation cannot be performed.
③Sensors can be easily installed on site. For single-plane balancing, one speed sensor and one vibration sensor are required; for double-plane balancing, one speed sensor and two vibration sensors are required. These are prerequisites for dynamic balancing instrument measurement.
7.3, How to improve the measurement accuracy of the dynamic balancing instrument
The dynamic balancing instrument is different from the dynamic balancing machine. The dynamic balancing machine has both an electrical control part and a mechanical part that supports the rotor operation. The dynamic balancing instrument only has an electrical control part; the mechanical part that supports the rotor operation is provided by each user; on site there are imported equipment; domestic equipment; equipment produced by various factories themselves; temporarily welded equipment, and the machining accuracy of various equipment is different, with great differences. In addition, the on-site testing environment is also different; some have large interference, some have small interference. This causes the balancing instrument to have different measurement accuracy at different factories, and it is impossible to give a unified measurement accuracy standard. In this instrument, there is only one technical indicator: unbalance reduction rate ≥90%, which is also relatively general. On imported equipment; domestic equipment can achieve this indicator, on equipment produced by various factories themselves can only approach this indicator, and on temporarily welded equipment on site it is difficult to achieve this indicator. In short, the measurement accuracy of the dynamic balancing instrument depends on the accuracy level of the equipment supporting the rotor operation; the higher the accuracy level of the equipment, the higher the measurement accuracy of the dynamic balancing instrument.
7.4, How to improve the measurement accuracy of the dynamic balancing instrument
The dynamic balancing instrument is different from the dynamic balancing machine. The dynamic balancing machine has both an electrical control part and a mechanical part that supports the rotor operation. The dynamic balancing instrument only has an electrical control part; the mechanical part that supports the rotor operation is provided by each user; on site there are imported equipment; domestic equipment; equipment produced by various factories themselves; temporarily welded equipment, and the machining accuracy of various equipment is different, with great differences. In addition, the on-site testing environment is also different; some have large interference, some have small interference. This causes the balancing instrument to have different measurement accuracy at different factories, and it is impossible to give a unified measurement accuracy standard. In this instrument, there is only one technical indicator: unbalance reduction rate ≥90%, which is also relatively general. On imported equipment; domestic equipment can achieve this indicator, on equipment produced by various factories themselves can only approach this indicator, and on temporarily welded equipment on site it is difficult to achieve this indicator. In short, the measurement accuracy of the dynamic balancing instrument depends on the accuracy level of the equipment supporting the rotor operation; the higher the accuracy level of the equipment, the higher the measurement accuracy of the dynamic balancing instrument.
