What is Blower Motor? its Diagram and How it Works
The blower motor is a crucial component in HVAC systems, responsible for pushing heated or cooled air through dashboard vents. It operates based on climate system settings and fan speed, which can be adjusted through a resistor.
Understanding the blower motor is essential for troubleshooting HVAC issues, as it powers the circulation of heated and cooled air, ensuring comfort throughout the year.
While not every detail of the HVAC system is essential, understanding it simplifies operation and occasional troubleshooting. Well, in this reading, we’ll explore what a blower motor is, its applications, location, parts, diagram, types, classifications, symptoms and causes of bad ones.
Let’s begin!
What is a Blower Motor?
The blower motor is a fan that circulates heated or cooled air through dashboard vents, influenced by the climate system settings and fan speed.
The motor’s speed is adjusted through a resistor, which controls the amount of current flowing to the motor. If the motor fails, only a small amount of air enters the interior vents, depending on the amount of outside air entering the climate system.
To ensure the motor’s functionality, check the fuses, which are usually located under the dashboard on the passenger side.
Blower motors that make loud squeaks or rattling noises may be worn out, or they may be caused by debris that can be cleaned after removal.
A blower motor is a fan in a forced-air heating and cooling system that blows air around the inside of a home and forces it back into the HVAC for reheating or cooling.
It is used in furnaces, air conditioners, heat pumps, and ductless mini-splits. When the thermostat senses a temperature drop outside the programmed comfort zone.
The blower motor activates the fan, forcing hot or cold air out of the unit, through ductwork, or directly from the air handler in ductless systems.
The blower motor’s location depends on the type of system. A furnace blower motor is typically found near the air filter, while an air conditioner shares the furnace’s blower motor for cooling. Heat pump blower motors are typically located in the air handler.
Applications
A blower motor is a crucial in the operation of electrical equipment in manufacturing plants. It is used for cooling devices and electrical equipment, such as seat ventilation, seat heating/cooling blowers, HVAC blowers, DC-DC converter cooling blowers.
They are also used in HEV/EV battery cooling blowers, fuel cell oxygen supply blowers, and air purifier blowers.
In commercial products, it is used for air intake, suction, vacuum gripping, transportation, dust extraction, ventilation, air supply, blowing, aeration, and drying or cooling processing materials.
The blower motor is essential for various applications in manufacturing plants, such as press and welding machines, food and textile manufacturing, and medical equipment.
Blower motors (blowers) are classified into four types: axial, diagonal, centrifugal (radial), and cross flow.
Axial Flow
Axial flow blowers use blades that move air parallel to the rotating shaft, increasing air volume and efficiency even with partial loads. However, due to their noisy structure, they can produce a jarring sound when switched on.
These types are used in various applications, from small, easy-to-disassemble blowers to powerful, large ones, and are suitable for both small and large-scale operations.
Diagonal Flow
Diagonal flow blowers have an impeller inclined at a constant angle, allowing air to flow in the same direction. They have intermediate characteristics between centrifugal and axial flow types, and their operating principle is similar to that of the centrifugal flow type.
Centrifugal Flow
Centrifugal flow blowers utilize centrifugal power from impeller rotation to increase air kinetic energy. Air near the impellers is thrown off and moves into the casing, measuring kinetic energy as pressure due to resistance. The air is guided to the exit via outlet ducts.
These blowers are used in various applications like leaf blowers, hair dryers, and climate control in air handling units. They can be classified into multi-blade (sirocco) type and turbo type.
Multi-blade type blowers have perpendicular air flow perpendicular to the axis of rotation, with forward-angled blades, and are used in duct ventilation, air conditioning, and cooling.
Turbo-type blowers have perpendicular air flow perpendicular to the axis of rotation, with backward-angled blades, and are used in vacuum cleaners and dryers. Both types have mid-range flow rates and high pressure.
Cross Flow
Cross flow blowers are air conditioners that suck in air from one direction and blow it from a 90° direction. They have an even air volume, can be easily extended and reduced in size, but have limited pressure, making them popular in HVAC.
Causes and Symptoms of a Bad Blower Motor
Blower motor failure can occur due to various factors such as moisture buildup, debris accumulation, worn-out bearings, blower motor resistor or fan issues, temperature control problems, electrical challenges, and old age.
Moisture buildup can cause corrosion and electrical shorts, while debris accumulation can cause overheating or failure. Worn-out bearings can overwork the motor, leading to premature failure.
Issues with the resistor or fan can result in system inefficiencies and require expert repair. If the motor cannot effectively manage temperature, it may run constantly, leading to wear and tear and eventual failure.
Electrical challenges, such as defective wiring, can lead to irregular motor operation or a full-blown breakdown. As blower motors age, parts wear out and failure becomes more likely.
A bad blower motor can cause discomfort and inefficiency in your home. Look for signs such as weak or no airflow from vents, unusual noises like grinding or squealing, burning smells, increased energy costs due to the motor running harder than necessary, and HVAC unit overheating.
A complete loss of airflow may indicate total motor failure, requiring prompt evaluation from a knowledgeable HVAC professional. Odd noises like grinding or squealing may indicate worn-out bearings or a misaligned motor.
Burning smells may indicate an overheating motor, requiring immediate intervention. Increased energy costs can result from the motor running harder than necessary, causing a noticeable spike in electric bills.
The HVAC blower motor is the component that turns on your system’s fan, pushing the hot or cold air out of the unit and into your home.
Air heating systems such as electric and gas furnaces, air conditioners, heat pumps, and mini-splits all utilize a blower motor to transfer this air.
What is the function of a blower?
Blowers are used mainly to circulate the movement of air to ventilation and applications. Their main function is to replace contaminated/impure air with fresh air by swirling it around.
What is the function of the blower motor in a car?
The blower motor is the fan that pushes heated or cooled air through dashboard vents based on the climate system settings and the fan speed selected. Adjusting the fan speed sends a signal through a resistor to the blower motor to either pick up the pace or slow it down.
