Addressing Common Contactor Issues

In recent decades, remarkable advancements in the fields of electricity and electronics have led to an increased demand for more complex and intelligent electrical systems. Contactors play a crucial and vital role in establishing and managing electrical connections. However, the problems and issues that may arise with contactors require careful attention and management to ensure the proper functioning of these essential components.

The importance of the correct performance of contactors is evident from various perspectives. Economically, the failure of a contactor can increase the costs of repairs and replacement of other parts, consequently reducing equipment efficiency. From a safety standpoint, improper functioning of contactors can pose serious hazards to both employees and electrical equipment.

In this article, we delve into the examination and resolution of common contactor issues. We aim to provide solutions and measures based on prevalent weaknesses in these devices, aiding in increasing the useful life, efficiency, and safety of contactors. This research will not only assist engineers and electronics specialists but also provide valuable insights to all individuals and companies utilizing such equipment, helping them familiarize themselves with potential challenges and consider optimal solutions to enhance contactor performance.

Internal Structure and Operation of Contactors

The internal structure of contactors is meticulously designed to enhance their performance. By utilizing a combination of switches, electromagnetic components, and contacts, contactors can manage and control electrical currents while incorporating protective settings to prevent unstable connections and safeguard systems. These devices hold significant importance in ensuring proper and safe electrical operations.

Contactors Structure

Core and Magnet

Core: The core of a contactor, known as a primary component, is typically made of silicon steel or stainless steel. The core’s function is to create a path for magnetic flux to generate a magnetic field.

Magnet: The magnet is usually positioned around the core and serves as an active element to attract switches (contacts) and induce current in coils at low voltage.


Coils, or markontactors, are vital components of contactors. These coils are made of wound conductive materials such as copper or aluminum and move in response to the magnetic field created by the core and magnet. This movement facilitates the opening and closing of switches.

Switches (Contacts)

Switches or contacts play a crucial role in contactors. These switches open and close, thereby establishing or interrupting electrical connections. Switches can be mechanical, electromagnetic, or a combination of both.

Control and Protection Section

Relays: The control section of contactors includes relays and electronic components used to control current, voltage, and protect the contactor. Relays play a vital role in managing the performance of contactors by generating necessary signals and controls.

Contactors Operation

Interrupting and connecting electrical currents

The primary function of contactors is to interrupt and connect electrical currents in electrical circuits. By pressing a button or applying a magnetic field, switches in the contactors become active, establishing or breaking electrical connections between circuits.

Current and Voltage Control

Contactors provide the ability to control electrical current and voltage. By changing the status of switches and adjusting various settings, electrical current and voltage can be precisely regulated as needed.

Equipment and User Protection

Contactors have various protective features used to prevent electrical hazards for equipment and users. These features include protection against excessive current, voltage, and temperature rise.

Specific Applications

Contactors are used in various applications, including:

– Controlling and managing motors and industrial electrical devices.

– Use in automotive systems to control electrical systems and lighting.

– Controlling and managing lighting systems and automatic lighting in buildings and public lighting systems.

Types of Contactors

It should also be noted that contactors come in various types such as brake type, regular type, and air-type, each serving specific applications.

Causes of Contactors Malfunction and Solutions

Short Circuit:

Causes: External particles, improper pressure on switches, or internal component failure.

Explanation: This issue can lead to increased current and voltage, resulting in switch malfunction and contactor failure.

Solution: Regular cleaning inside the contactor, especially at the switch location, using suitable materials to prevent the entry of external particles, and repairing chips and electrical contaminants.

Welding due to Electrical Shock:

Causes: Electrical shocks due to improper working conditions or system defects.

Explanation: Electrical shocks can cause welding in switches and affect the proper operation of the contactor.

Solution: Improving working conditions, using shock-resistant equipment, and avoiding sudden electrical disconnections.

Non-Movable Iron Core:

Causes: Insufficient magnetic pressure, structural defects, or physical damage to the core.

Explanation: An immovable iron core may prevent proper closing or opening of switches.

Solution: Ensuring sufficient magnetic pressure in the core, correcting structural defects, and preventing physical damage to the core.

Overheating or Burning of Coil Wires:

Causes: Excessive electrical current, defects in the cooling system, or improper pressure on the coil wire.

Explanation: Coil wires overheating can lead to contactor failure due to excessive heat.

Solution: Reducing electrical current, ensuring optimal performance of the cooling system, and correcting improper pressure on the coil wire.

Delayed Release or Inability to Release the Iron Core:

Causes: Jamming, uneven pressures, mechanical damage, or wear in the core’s movement path.

Explanation: An iron core that cannot release properly can adversely affect the contactor’s operation.

Solution: Removing jams, rectifying uneven pressures, preventing mechanical damage to the core’s movement path, and addressing wear in the core’s movement path.

Incorrect Installation:

Causes: Improper installation or misalignment of the contactor, loose terminals, or inadequate connections.

Explanation: Incorrect installation can lead to improper switching and contactor failure.

Solution: Proper installation of the contactor and ensuring correct alignment of terminals and connections. Ensure all components are installed correctly according to the manufacturer’s guidelines.

Inadequate Repair and Maintenance:

Causes: Failure to carry out timely repairs, lack of maintenance, and failure to replace worn-out parts.

Explanation: Improper repairs and inadequate maintenance can lead to improper switching and contactor failure.

Solution: Timely repairs, regular maintenance, and replacement of worn-out parts following the manufacturer’s guidelines.

Electrical Overload:

Causes: Using the contactor in electrical currents and loads exceeding the permissible limit.

Explanation: Increased electrical load can lead to improper switching and contactor failure.

Solution: Using a contactor with electrical capacity according to the requirement, ensuring the contactor’s electrical specifications match the working conditions.

Misalignment of the Contactor or Loose Terminals:

Causes: Improper installation or misalignment of the contactor, loose terminals, or inadequate connections.

Explanation: Misalignment of the contactor or loose terminals can lead to improper switching and contactor failure.

Solution: Proper alignment of the contactor, use of quality terminals, and correct connections prevent improper switching and contactor failure.

Ingress of Contaminants and Unintended Environmental Factors into the Contactor Enclosure:

Causes: Entry of water, dust, chemicals, or other environmental factors into the contactor enclosure.

Explanation: Contaminants and environmental factors may affect the conductive surfaces and lead to contactor failure.

Solution: Use protective contactors with waterproof, dustproof standards, and resistance to specific environmental conditions.

Extended Lifespan of the Contactor and Internal Components:

Causes: Prolonged use of worn-out contactors and components without replacement.

Explanation: Prolonged use of worn-out contactors and components can lead to improper switching and contactor failure.

Solution: Timely replacement of worn-out components, regular maintenance, and use of quality and replaceable contactors.

Voltage Coil Instability:

Causes: Excessive voltage fluctuations in the coil’s power supply.

Explanation: Excessive voltage fluctuations in the coil’s power supply can result in contactor instability and failure.

Solution: Use voltage stabilizer equipment or ensure proper voltage balance in the power grid, and ensure coil power supply stability.

Causes and Solutions for Contactors Chattering

Contactor chattering or rapid switching off usually results from sudden disconnection or electrical issues in the system. The reasons for contactor chattering can vary, but some main causes include:

High Current or Short Circuit:

Sudden increase in electrical current due to a short circuit in the system or heavy load can cause contactor chattering.

Electrical Shock:

Electrical shocks or sudden electrical disconnections can cause contactor chattering.

Voltage Fluctuations:

Voltage fluctuations in the power grid can lead to sudden disconnections and contactor chattering.

Use of Undersized Contactors:

Using a contactor with a capacity lower than the electrical load requirement can lead to chattering.

Contactor Component Failure or Wear:

Failure in internal contactor components or wear in coil wires and mechanical parts can cause chattering.

Faulty Connections and Terminals:

Incorrect connections or loose terminals can generate excessive heat and consequently cause chattering.

To address these issues and prevent contactor chattering, the following actions can be taken:

1. Ensure selecting a contactor with appropriate capacity based on the electrical load.

2. Inspect and correct connections and terminals to prevent loosening or improper connections.

3. Use effective protections to prevent short circuits or high currents.

4. Monitor the power grid closely and use voltage stabilizer equipment in case of fluctuations.

5. Regularly inspect and maintain internal contactor components to prevent failure and wear.

In summary, rectifying contactor issues is a crucial process for safety and proper operation of electrical systems. Since contactors are essential elements in controlling and managing electrical loads, their issues can lead to serious risks and sudden failures.

Initially, selecting the right contactor considering the electrical load requirements and environmental conditions is of utmost importance. Not only can this action increase the contactor’s lifespan, but it can also prevent failures resulting from improper selection.

Regular monitoring and timely maintenance are also highly important. Through these actions, problems can be quickly identified and resolved. The use of diagnostic techniques can also assist in accurate and rapid error detection.

Furthermore, the use of electrical protections plays a fundamental role in preventing short circuits and mitigating electrical hazards. Moreover, employee training on the proper use and installation of contactors is of significant importance.

Overall, given the importance of electrical systems, performing regular care and maintenance of contactors improves their performance and safety, ultimately helping to prevent potential issues and damages.

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top