could an ac contactor burn out a condenser fan motor


Is an AC Contactor Capable of Burning Out a Condenser Fan Motor?


When it comes to the smooth operation of an air conditioning system, all the components need to work together harmoniously. Among these components, the AC contactor and the condenser fan motor play crucial roles. The AC contactor is responsible for controlling the flow of electricity to the condenser unit, while the condenser fan motor helps to dissipate heat from the system. However, there has been speculation that the AC contactor could potentially burn out the condenser fan motor. In this article, we will delve into this topic and assess the validity of such claims.

The Role of the AC Contactor

The AC contactor is an essential electrical component in an air conditioning system. It acts as a switch, allowing or interrupting the flow of electricity to the condenser unit. The contactor contains a set of large springs and an electromagnet. When the thermostat signals the need for cooling, a low-voltage signal is sent to the contactor, energizing the electromagnet.

As the electromagnet becomes energized, it pulls the contacts together, completing the circuit and allowing electricity to flow to the condenser unit. Conversely, when the cooling demand ceases, the low-voltage signal stops, and the electromagnet is de-energized. This causes the contacts to separate, interrupting the flow of electricity.

The Functions of the Condenser Fan Motor

The condenser fan motor, on the other hand, plays a crucial role in the heat dissipation process of an air conditioning system. It is responsible for blowing air over the condenser coil, facilitating the transfer of heat from the refrigerant to the outdoor air. Without the condenser fan motor, the condenser coil would not be able to effectively dissipate heat, resulting in higher pressure and temperature levels within the system.

The condenser fan motor operates using a set of windings that generate a magnetic field. As electricity flows through these windings, a magnetic field is produced, causing the motor to rotate. This rotation drives the fan blades, leading to the movement of air across the condenser coil.

Reasons for Speculation

There have been claims that the AC contactor could potentially burn out the condenser fan motor. These claims arise from various scenarios, including the high amperage and voltage spikes that occur during the switching process of the contactor. Additionally, poor electrical connections and excessive electrical arcing can occur within the contactor, potentially leading to damage to the fan motor.

Amperage spikes can occur during the startup phase of the contactor, as the motor requires a higher amount of current to overcome inertia and initiate rotation. Some argue that these spikes can exceed the motor's rated amperage, placing undue stress on its windings. Inadequate wiring connections or loose terminals in the contactor can also contribute to excessive heat generation, potentially damaging the motor over time.

The Truth Behind the Claims

While the claims regarding the contactor burning out the condenser fan motor may sound plausible, it is important to understand the overall functioning of the system and the protective measures in place. In reality, the AC contactor alone is unlikely to directly burn out the condenser fan motor.

Modern air conditioning systems are designed with protective devices and measures to prevent motor burnouts. Capacitors, for instance, are often installed within the system to manage voltage spikes and provide an initial surge of power to the motor during startup. These capacitors act as a buffer, minimizing the strain on the motor's windings.

Furthermore, most air conditioning systems utilize overload protectors or thermal cutoff switches, which automatically shut off the power supply to the motor if it exceeds a safe operating temperature. These protective devices prevent excessive heat buildup within the motor, mitigating the risk of burnouts.

Proactive Maintenance to Prevent Motor Issues

While the AC contactor itself may not be the primary cause of condenser fan motor burnouts, regular maintenance and inspections are essential to ensure the longevity of the system as a whole. Here are some key maintenance practices that can prevent motor issues:

1. Check and tighten electrical connections: Loose wiring connections can lead to arcing, generating excessive heat within the contactor. Regularly inspect and tighten all electrical connections to prevent such issues.

2. Clean the condenser coil and fan blades: Accumulated dirt and debris on the condenser coil and fan blades can restrict airflow, causing the motor to work harder and potentially overheat. Regular cleaning can prevent such issues.

3. Inspect and replace worn fan belts: Fan belts that are worn or loose can cause the motor to strain, leading to overheating. Replace worn belts promptly to prevent motor damage.

4. Maintain proper lubrication: Ensure that the condenser fan motor is properly lubricated to minimize friction and reduce strain on the motor.

5. Schedule regular professional maintenance: Hiring a professional technician for routine inspections and maintenance can help identify potential issues before they escalate, ensuring the optimal performance of the system.


In conclusion, the claims that an AC contactor can burn out a condenser fan motor are largely unfounded. While it is true that the contactor and the motor are interconnected within the air conditioning system, the design and protective measures in place make it unlikely for the contactor to be the sole cause of motor burnouts. By adhering to regular maintenance practices and inspections, including checking electrical connections and ensuring proper lubrication, homeowners and technicians can mitigate the risk of motor issues and aid in the overall longevity of the air conditioning system.


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