A Case Study Of Troubleshooting Three-Phase Induction Motor Shaft Issues


Client: Groundnut processing factory at Himmatnagar, Gujarat, India.

Motor Model: 40 HP / 6 Pole / IE-2 / F CLASS / 3PH


Lubi Induction Motors
Lubi Induction Motors


One of our valued clients recently purchased a new F-Class Induction Motor of our company to power their machinery. However, to their surprise, the motor's shaft broke after running for a short period of time.

Concerned about the issue, the operator promptly brought the motor to our service center. As the motor was still under warranty, we immediately replaced the rotor and conducted standard inspections before returning the motor to the operator.

Unfortunately, just one day later, the operator returned with the motor once again experiencing a broken shaft.

Recognizing the recurring problem, our support team decided to send an engineer to the client's factory to investigate the root cause behind the repeated shaft failures.


Our F-Class induction motor is renowned for its high quality and reliability. In the event of any issues with our motors or pumps, we strongly recommend contacting us through our toll-free number to report the problem.

This allows us to dispatch a trained professional who can conduct a thorough inspection and identify the underlying cause of the problems.


  1. Customers can register a complaint by calling our toll-free number, after which they will receive a text message with information about the complaint as well as the contact details of our service engineer.
  2. Our Engineer usually calls up to fix an appointment as per the electricity schedule of the area - as there are frequent power disruptions in some places.


Nameplate Of Motor
Nameplate Of Motor


Upon reaching the site, our service engineer immediately commenced the inspection to validate the reported problem and identify its root cause.

He first assessed the motor's foundation to ensure stability.

Note: The foundation of an F-Class induction motor should be solid and stable to ensure proper installation and operation. It should be constructed using a concrete base, designed to withstand the motor's weight and vibrations. Adequate reinforcement and levelling should be implemented to maintain the motor's alignment and prevent any movement or misalignment during operation.

Note: When attaching a pulley and belt-drive to an F-Class induction motor, it is important to ensure proper alignment and tension. The pulley should be securely mounted on the motor shaft with accurate alignment to minimize vibration and prevent belt slippage. The belt-drive system should be properly tensioned, maintaining the manufacturer's recommended tension levels, to ensure efficient power transmission and avoid excessive wear on the belt and pulley surfaces.

Our engineer then went on to thoroughly examine the He then assessed the motor’s speed (using a tachometer) and compared its value to the speed recommended by the equipment manufacturer.

Note: This comparison allows for a verification of whether the motor is operating within the prescribed speed range as advised by the manufacturer of the machinery.



While inspecting the foundation for the motor, our engineer found that its surface was uneven and unbalanced.


Old Foundation Pulley
Old Foundation Pulley


The motor had inadequate support and the materials used for base support were of sub-standard quality.

The engineer also observed that both the pulley and the belt drive exhibited signs of significant wear.

While checking the speed (RPM) of the machine, he observed that it exceeded the RPM recommended by the manufacturer.



Our engineer's visit proved instrumental in identifying multiple factors contributing to the motor's failure and damage.

Our engineer recommended the following remedial measures to the operator to avoid any future issues.

  • Firstly, he emphasized the importance of constructing a sturdy and well-levelled foundation for the motor. -Secondly, he advised the incorporation of heavy C Section Channels as a robust base plate or support for the machine.
  • Next, he recommended them to replace the pulley and the belt as they had both worn out.
  • Finally, he suggested them to buy a new pulley of appropriate size to ensure the motor operates within the manufacturer's recommended RPM range.
New Installtion New Pulley New Belt
New Installtion New Pulley New Belt


The operator diligently adhered to our engineer's recommendations and implemented all necessary changes. Upon installation of the motor, it was observed that the motor operated smoothly, devoid of any vibrations or undesirable noise. 


New Foundation
New Foundation


  1. The F-Class induction motor is a very powerful machine which plays a significant role in a groundnut processing factory. It is typically utilized to power various machinery and equipment involved in groundnut processing operations. This motor provides the necessary power and torque to drive machines such as groundnut cleaning and sorting equipment, oil extraction machines, and other auxiliary systems within the factory.
  2. The recommended power supply for a three-phase F-Class induction motor is 280 to 415 Volts.
  3. Ensure that the belt and pulley are properly fitted and that the tension is appropriate before starting the motor.
  4. Make sure your motor operates at the load as declared by the manufacturer. Please contact our customer support team to learn more.
  5. Regular lubrication of the motor is crucial to ensure its optimal performance. 6)Regular inspection and servicing of the motor can help detect many issues beforehand.


For smooth and uninterrupted working of your motor, always follow the instructions and standard operating procedure issued by the manufacturer in the user manual.