Dynamic Balancing Measuring Instrument

The VT800 dynamic balancing instrument can perform on-site dynamic balancing for various types of rotating machinery, equivalent to a portable dynamic balancing machine. It is exquisitely designed and easy to carry, with the entire instrument housed in a portable case. In addition to general dynamic balancing functions, the VT800 is specially designed for the overall dynamic balancing of horizontal spiral centrifuges and disc centrifuges,enhancing anti-interference capabilities and enabling convenient measurement of vibration in differential speed composite drum bodies, as well as on-site overall dynamic balancing.Technical Parameters

1. General Measurement:

Speed Measurement: 30～30,000 rpm

Vibration Measurement: 0.01～5000μm (peak-to-peak)

0.01～2000mm/s (RMS)

Vibration Analysis: FFT spectrum analysis

Display Method: Dot matrix graphics 64X240 dot matrix graphical LCD with Chinese menu

Keyboard: Eight keys

2. Dynamic Balancing Measurement:

Measurement Points: Dual-channel single measurement point or single plane, dual measurement points or dual planes

Vibration Signal Bandwidth: 3Hz～1KHz

Operating Speed Range: 180～30,000 rpm

Amplitude Range: 0.01～5000μm (peak-to-peak)

Vibration Severity Range: 0.01～2000mm/s (RMS)

Phase Accuracy: 0-360°

Unbalance Reduction Rate: 90%

Several Issues in Dynamic Balancing Measurement

 7.1, Confirming Whether Rotor Equipment Vibration is Caused by Unbalance

First, confirm whether the rotor equipment vibration is caused by unbalance. Field equipment vibration is complex, generally mixed-frequency vibration. Only when the unbalance vibration component accounts for more than 80% of the total mixed-frequency vibration can this instrument show effective results. Specifically, use the instrument's "Signal Analysis" and "FFT Analysis" functions to perform spectrum analysis on the vibration signal. Through spectrum analysis, if the fundamental frequency vibration is large and other harmonic vibrations are small or even absent, using this instrument's operations 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 indicates that the unbalance value accounts for a large percentage of the total vibration, and the dynamic balancing measurement effect is significant. 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:

① Within the operating speed range, multiple start-stop operations can be performed. Specifically, using the trial weight method, at least 3 starts are required for single-plane balancing and at least 4 starts for dual-plane balancing to see the dynamic balancing effect.

② It should be convenient to add or remove weight from the rotor on-site. Any enclosed rotating rotor or shaft system, or where adding or removing weight on the rotor correction plane is not allowed, cannot undergo dynamic balancing operations.

③ Sensors should be easily installed on-site. Single-plane balancing requires one speed sensor and one vibration sensor, while dual-plane balancing requires one speed sensor and two vibration sensors. These are prerequisites for dynamic balancing instrument measurements.

7.3, How to Improve the Measurement Accuracy of the Dynamic Balancing Instrument

The dynamic balancing instrument is different from a dynamic balancing machine. The dynamic balancing machine has both electronic control parts and mechanical parts that support rotor operation. The dynamic balancing instrument only has electronic control parts, and the mechanical parts supporting rotor operation are provided by users; on-site, there are imported equipment, domestic equipment, self-produced equipment by various factories, and temporarily welded equipment. The machining accuracy of various equipment varies greatly. Additionally, on-site testing environments differ, with some having high interference and some low. This results in varying measurement accuracy of the balancing instrument at different manufacturers, and it is impossible to provide a unified measurement accuracy standard. This instrument only has one technical indicator: unbalance reduction rate of 90%, which is relatively general. This indicator can be achieved with imported and domestic equipment, approached with self-produced equipment by factories, but is difficult to achieve with temporarily welded on-site equipment. In summary, the measurement accuracy of the dynamic balancing instrument depends on the accuracy grade of the equipment supporting rotor operation. The higher the accuracy grade of the equipment, the higher the measurement accuracy of the dynamic balancing instrument.

7.4, Differences Between Dynamic Balancing Instrument and Dynamic Balancing Machine

Advantages of on-site dynamic balancing instrument:

① On-site balancing is performed on fully assembled machines, compensating for assembly errors.

② There is no need to disassemble the machine or transport the rotor to a dynamic balancing machine, saving time, reducing costs, and minimizing downtime losses.

③ The on-site dynamic balancing instrument can balance rotors of any weight and size. Dynamic balancing machines have certain regulations and requirements for rotor weight and size.

④ Lower investment cost; dynamic balancing machines cost from tens of thousands to over a hundred thousand yuan, while a portable dynamic balancing instrument generally costs below 10,000 yuan.

7.5, Comparison of Three Types of Speed Sensors

Speed sensors include photoelectric speed sensors, Hall speed sensors, and laser speed sensors (optional accessory).

This instrument is shipped with a photoelectric speed sensor. The advantages of the photoelectric speed sensor are: only a white double-sided reflective sticker is needed for speed measurement, with no additional mass, making it simple and easy to use. The measurement distance is 1-30 cm, basically meeting on-site measurement needs. The disadvantage is susceptibility to light and distance influences, sometimes requiring repeated adjustments of the white sensitivity knob on the photoelectric sensor.

The advantages of the Hall sensor are: good output pulse, strong anti-interference capability, and simple on-site installation. Once aligned with the配套 small magnet, no adjustments are needed during measurement. The disadvantages are: the small magnet itself has mass, affecting measurement accuracy, and it may fly off during high-speed rotation. If there are holes, grooves, or flanges on the plane, it can be firmly attached with 502 glue. It can be considered for use at operating speeds below 1500 rpm.

The laser speed sensor is a recently developed type of speed sensor that can measure speeds up to 60,000 rpm, suitable for high-speed measurements. Its testing method is the same as the photoelectric speed sensor. It has stronger anti-interference capability than the photoelectric sensor, longer measurement distance, requires no adjustments, and provides stable and reliable readings. The disadvantages are: it requires special reflective paper with high requirements for reflective markers. The greater the contrast between the reflective paper and the measured object's color, the better the measurement results. Generally, painting black paint or pasting black electrical tape is required to increase contrast. The laser speed sensor needs to be purchased separately.