Step-by-Step Guide to Motor Overhauling: A Complete Procedure

Motor overhauling is the process of restoring or repairing defective electric motors to their original condition (or) higher performance levels. The purpose is to restore the motor to its optimum operational state, either by repairing or replacing problematic components. 

Motor overhauling is defined as a variety of procedures and processes that are dependent on the motor’s make, model, and cause of failure.

In this post, we will go deeper into an array of motor overhauling procedures and look at some significant aspects that influence the progress of the process.

Introduction

Electric motors are essential components in a variety of sectors and environments, ranging from domestic appliances to heavy gear in factories and mining. 

However, with continued usage and the passage of time, motors can fail, resulting in costly downtime & operational problems. Without quick action, the implications might range from small problems in manufacturing to catastrophic failure, needing a total overhaul. 

In this post, we will look at the procedures used in motor overhauling, as well as some important factors for best outcomes.

1). Diagnosis

Motor overhauling starts with identifying the root cause. 

Identifying and resolving fault sources is critical to avoiding recurrence of issues following overhauling. 

Understanding the motor’s design and faults might help us reorganize it effectively. 

Faults can occur from a variety of sources, including pollution, winding failure, bearing difficulties, lubrication failure, and thermally induced damage caused by misapplication (or) electrical disturbances. 

As a result, doing a thorough inspection of the motor is critical to accurately identifying the problem.

2). Component Replacement

Component replacement is important in overhauling. 

The method needs the removal of fault components and their replacement with high-quality counterparts. 

• Bearings, 
• Windings, 
• Capacitors, & 
• Commutators 

are some of the most often replaced important components. 

Capacitor: Because of their sensitivity, capacitors are frequently replaced; timely replacement could significantly extend the motor’s lifespan. 

Winding: Windings, on the other end, present a greater difficulty, necessitating careful consideration and experience to ensure the best possible results.

3). Winding Consideration

When deal with windings, several elements must be considered ahead of time because they have a considerable impact on overall performance. 

The insulating material, form, and design have a significant impact on the electric character of the winding as well as the mechanical properties of the motor. 

Furthermore, the type of winding pattern utilized has a significant impact on the motor’s output, which must be chosen according to the motor’s intended application. 

Insulation resistance measurement is also an important part in determining the end-of-life state & resilience of the winding & insulation system.

4). Motor Rewinding

When winding failure develops in motors, thorough rewinding is required to ensure efficient & effective motor performance. 

The operation requires the skillful hands of highly experienced specialists who have been trained in the proper rewinding techniques for a certain motor type. 

A good rewinding requires the precise application of the correct winding procedures, high-quality materials, winding alignment & concentricity, as well as satisfying the manufacturer’s specifications. 

Although expensive, motor rewinding processes result in much longer motor working lifetimes and massive savings by eliminating replacement expenses.

The methods of motor overhauling essentially entail detailed diagnostics, component replacement, a selective approach to winding concerns, and motor rewinding, when applicable. 

Proper overhauling methods assure high quality output, efficient & long-lasting motor performance, and significant cost savings.

To get the intended results, it is essential to take caution & prioritize quality throughout the overhauling process.

Importance of Motor Overhaul

Motor overhauling, an essential aspect of industrial machinery maintenance, is the process of restoring malfunctioning (or) worn-out motors to their functioning original state. 

This method not only extends the equipment’s life, but it also increases efficiency and lowers operational costs. 

Motor overhauling involves a wide range of approaches that are determined by the type of motor, its age, and the cause of failure. 

Winding repair, rotor balance, bearing replacement, and commutator reconditioning are some common procedures. 

Types of Motor Overhauling

Motor overhauling is an essential operation in any industrial facility that entails disassembling, inspecting, fixing, & reassembling an electric motor in order to restore the original performance. 

There are 2 types of motor overhauling: 

1. Rewinding and 
2. Rebuilding. 

1). Rewinding 

Rewinding is the process of wrapping fresh coils into the rotor & stator slots, whereas rebuilding involves completely disassembling, repairing, and replacing all broken components. 

2). Rebuilding

Motor overhauls may be required for a variety of reasons, which includes age-related wear, overloading & thermal (or) electrical damage, 

Proper motor overhauling methods can assist extend the motor’s life, enhance efficiency, and reduce maintenance costs, making it an essential activity for any facility that relies on electricity to function.

NEMA MG1 for motor performance, IEEE 43 for insulation testing, & IEC 60034 for repair instructions are some of the key standards. ISO standards, such as ISO 9001 and ISO 1940-1, ensure quality management and appropriate balancing, whereas ANSI/EASA AR100 focuses on maintaining motor efficiency after maintenance. OSHA’s safety measures are also essential. These standards ensure that motor overhauling is safe, dependable, and effective at extending motor life & performance.

Basic Motor Overhauling Procedure

Basic motor overhauling: Step-by-Step Procedure

Step 1: Inspection

Motor overhauling starts with a thorough inspection. This includes physically inspecting the exterior, frame, & rotor, as well as performing diagnostic tests to discover any internal problems. 

Inspection allows us to identify particular sections that need repair or replacement, lowering the overall cost & time necessary for overhauling.

Step 2: Disassembly

After diagnosing the defects, dismantle the motor to find the components that need to be repaired or replaced. 

This involves removing

• Stator,
• Rotor,
• Bearing Assemblies, 
• End Rings, & 
• Labels. 

Proper identification of each part facilitates re-centering the motor during reassembly & assures that all components are returned to their proper placements.

Step 3: Repair and Replacement

The next step after disassembly is to repair & replace any detected defects. Bearings and broken insulation, for example, may need cleaning, resizing, or replacement. 

The field winding, stator slots (or) rotor coils, may need to be replaced if they appear worn, pitted, (or) beyond repair.

Step 4: Cleaning & Lubrication

Cleaning & lubricating the motor’s inner and exterior are important steps in the overhauling process since they have a substantial impact on how the motor operates. Debris, moisture, oil, & dirt can all interfere with the motor’s performance, resulting in poor operation (or) failure. 

Clean all replaceable parts, including bearings, frames, & tips, & lubricate the rotor & bearing assemblies.

Step 5: Rewinding

Depending on the kind of motor and its intended use, rewinding – which involves wrapping rotor, stator, and any additional coils – is optional. Modern AC motors, 

Ex: No longer require rewinding because slot winding technology allows for the replacement of damaged copper bars, which eliminates the requirement for rewinding in the vast majority of cases.

Step 6: Reassemble

After completing all necessary repairs, reassemble the motor, reinstalling bearings, shaft seals, winding cables & other necessary components to their original positions. Accurate reassembly not only assures smooth functioning, but also decreases noise and vibration, extending the motor’s life.

Step 7: Testing

After reassembly, test the motor to confirm it is fully operational. To reduce noise levels, use soft starts and operate it at full load to make sure that the operating temperature remains within the required ranges. A visual check is also required to verify clean and precise winding arrangements.

Following that, motor overhauling is a complex operation that requires both technical skill and expertise. By closely following the above motor overhauling procedures, you may ensure effective motor maintenance while lowering total maintenance and repair expenses.