Forest Mulcher Rotor Balancing: Key to Efficient Operation

Forest mulchers are powerful machines designed to shred vegetation and create firebreaks. At the heart of the mulcher is a rotor equipped with special knives or teeth, rotating at high speeds to grind trees and shrubs. However, due to intense use and external factors, the rotor can become unbalanced, leading to vibrations.

What is Imbalance?

Imbalance is a condition where the rotor's mass is unevenly distributed relative to its axis of rotation. This results in centrifugal forces that cause unwanted vibrations. Vibration, in turn, can lead to accelerated bearing wear, damage to other mulcher components, reduced efficiency, and even breakdowns.

There are two main types of imbalance: static and dynamic.

Static Imbalance

Static imbalance occurs when the rotor's center of gravity is offset from its axis of rotation. This causes the rotor to seek a position where its heavier part is at the bottom. Static imbalance can be detected even when the rotor is not rotating.

An example of a rotor with the static imbalance is presented in Fig.2

Dynamic Imbalance

Dynamic imbalance arises from uneven mass distribution along the length of the rotor. In this case, forces and moments are generated during rotation, causing additional vibrations. Dynamic imbalance manifests only when the rotor is rotating.

Dynamic imbalance of rotor – couple of the centrifugal forces

Why Can't You Correct Dynamic Imbalance Without Equipment?

Many mechanics and operators try to correct imbalance "by eye" by adding or removing weights on the rotor without using specialized equipment. However, this approach is only effective for static imbalance. With dynamic imbalance, where heavy points are in different planes of the rotor, it is nearly impossible to visually determine their location and the necessary mass correction.

To eliminate dynamic imbalance, specialized equipment is needed – portable balancers that can accurately measure vibration amplitude and phase, and calculate the necessary corrective weights and their installation locations.

Disadvantages of Increased Vibration

Increased rotor vibration can lead to several negative consequences:

Accelerated wear of bearings, shaft, housing, and other components
Damage to the hydraulic system and tractor engine
Reduced productivity and increased fuel consumption
Poor working conditions for the operator, increased fatigue, and risk of occupational diseases
Increased risk of accidents

Field Balancing: Saving Time and Money

Field balancing of the mulcher rotor using a portable balancer is an effective solution that avoids the costly process of disassembly, transportation, and reassembly of equipment. You can quickly eliminate imbalance and resume work, minimizing downtime and saving time and money.

Step-by-Step Balancing Process with Balanset-1A

Preparation: Attach vibration sensors to the mulcher housing near the rotor bearings. The sensors should be oriented perpendicular to the rotor's axis of rotation. Attach a reflective marker to the rotor or pulley. Mount the tachometer on a magnetic stand so that its laser beam hits the reflective marker. Connect the sensors to the "Balanset-1A" device, which in turn is connected to a laptop. Launch the specialized balancing software.
Initial Measurement: Select the two-plane balancing mode in the software. Weigh the calibration weight and enter its weight and installation radius into the program. Start the mulcher rotor and measure the initial vibration level.
Balancing in the First Plane: Install the calibration weight on the rotor in the first correction plane (usually closer to one of the bearings). Restart the rotor and measure the vibration. Ensure that the vibration or phase changes are at least 20%.
Balancing in the Second Plane: Move the calibration weight to the second correction plane (usually closer to the other bearing) and conduct a third vibration measurement during rotation.
Data Analysis: Using the obtained data, determine the corrective weights and their installation locations for balancing the rotor.
Installing the Corrective Weights: Install the corrective weights on the rotor at the locations specified by the program.
Verification: Measure the vibration levels after installing the weights and ensure that the vibration is reduced to an acceptable level. If necessary, add or remove part of the corrective weight and recheck the balance.

Balanset-1A: Your Reliable Partner in Rotor Balancing

The "Balanset-1A" is a portable balancer and vibration analyzer, perfect for balancing rotors of various types and sizes, including forest mulcher rotors.

Main Advantages of Balanset-1A:

Ease of Use: Balanset-1A is easy to learn and use, even for those without specialized knowledge in vibration.
Portability: Compact and lightweight, the device is easy to transport and use on-site.
High Accuracy: Balanset-1A provides high measurement accuracy, ensuring quality balancing.
Multifunctionality: The device can be used not only for balancing but also for vibration analysis and equipment diagnostics.
Affordable Price: Balanset-1A offers excellent value for money, making professional balancing accessible to a wide range of users.

Technical Specifications:

Range of RMS Vibration Velocity Measurement: 0.02 to 80 mm/s
Frequency Range of RMS Vibration Velocity Measurement: 5 to 550 Hz
Number of Correction Planes: 1 or 2
Range of Rotational Speed Measurement: 100 to 100,000 RPM
Range of Vibration Phase Shift Measurement: 0 to 360 degrees
Limits of Permissible Absolute Measurement Error of Vibration Phase Shift: ±1 degree

Package Contents:

USB interface block
Two vibration sensors
Optical sensor (laser tachometer) with magnetic stand
Scale
Software
Plastic carrying case

Devices