Balancing Electric Motor Rotors: Methodologies and Outcomes


The functionality and longevity of electric motors are profoundly influenced by the balance of their rotors. Especially after repair interventions, these rotors may exhibit imbalances that can reduce the efficiency and lifespan of the motors. Enterprises that specialize in motor repair often encounter this challenge. This article aims to elucidate the methodology of using specialized balancing equipment and the consequent outcomes, ensuring effective motor performance.

The Necessity of Balancing Equipment

Rotor imbalances can lead to an array of problems, including increased wear, reduced efficiency, and even equipment failure in severe cases. Hence, incorporating balancing procedures post-repair becomes imperative. Balancing equipment serves this purpose, providing an efficient and cost-effective solution to the enterprises.

Recommended Setup: A Simple Stand with Spring Dampers

To utilize the balancing equipment effectively, a specific setup is advised. This involves the construction of a stand, typically a welded frame, positioned on cylindrical spring dampers. Such a configuration offers several advantages:

  1. Isolation from External Vibrations: The spring dampers act as buffers, isolating the balancing process from external vibrations and disturbances. This ensures accuracy in the balancing procedure.
  2. Mitigation of Resonance Phenomena: In addition to providing isolation from external factors, the spring dampers are crucial in eliminating potential resonant conditions that could compromise the balancing process.
  3. Tuning the Natural Frequency: One crucial aspect to consider is the natural frequency of the frame oscillations on the dampers. When combined with the weight of the frame and the electric motor being balanced, this frequency should be approximately 2-3 times lower than the rotor’s rotational frequency.

Adhering to these conditions is paramount to achieve the desired outcomes.

Results of the Balancing Process

When the aforementioned conditions are met, the results are invariably positive. Post-balancing, the residual vibration levels of the electric motor, when measured using the specialized equipment, consistently lie in the range of 0.3-0.7 mm/s. In the realm of electric motors, such figures are indicative of a high level of balance, ensuring that the motor functions efficiently and is less prone to premature wear or failures.


Balancing electric motor rotors, especially post-repair, is a crucial step in ensuring the motor’s efficient and prolonged operation. By employing specialized balancing equipment and adhering to specific methodologies, such as using a stand on cylindrical spring dampers, enterprises can achieve commendable balancing outcomes. This not only enhances motor performance but also results in long-term economic benefits due to reduced wear and increased motor lifespan.

Fan balancing machine based on the Balanset-1A vibration analyzer.

Fan balancing machine based on the Balanset-1A vibration analyzer.