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How to Select the Right Cooling Fan

In many devices and systems, the buildup of heat can lead to reduced performance, prematurely deteriorated components and materials, and increased safety risks. For these reasons, many pieces of equipment utilize cooling fans to dissipate heat buildup and avoid these potentially costly consequences.

Since cooling fans are used in a wide range of products, they are available in a variety of designs and configurations to suit different application requirements and restrictions. While this broad selection makes it possible for product designers and engineers to find a component that meets their exact needs, it can also make it more challenging to find the right one. The following article serves as a helpful selection guide for readers, outlining the steps to follow when choosing a cooling fan for a particular application. 

The Cooling Fan Selection Process

Step 1: Perform a Thermal Analysis

The first step in the cooling fan selection process is performing a thermal analysis. A thermal analysis determines the amount of heat generated inside a particular piece of equipment or during a particular process. The result can be used to calculate the volume of air needed to cool the device or system. 

Thermal analysis operations use sensors and other instruments to determine the source(s) of heat and the amount of heat generated by each source. The heaviest consumers of power and, consequently, the biggest contributors to heat dissipation are often components like microcontrollers, processors, FPGAs, and MOSFETs. Once the necessary information is obtained, the amount of airflow required to cool the device or system can be calculated. Afterward, the cooling air path can be mapped using sensors and software to ensure that all major heat sources receive the air needed to cool them sufficiently. 

Step 2: Determine the System Impedance

After the thermal analysis is performed and the required air volume is calculated, the next step in the cooling fan selection process is determining the system impedance. System impedance refers to the sum of the pressure drop experienced as air travels between the fan’s inlet vents and exhaust vents. If a system has multiple air paths, the individual impedance values are added. The value(s) can be measured for different rates of airflow with pressure sensors or by placing the system in an air chamber. 

Step 3: Choose the Type of Fan

After the system impedance is identified, it can be used with the calculated airflow requirement to gauge the static pressure needed for the system. This information can then be utilized to determine which fan will serve as the best solution. 

Cooling fans are divided into two categories based on the way air flows through them. 

• Axial fans have air enter and exit in the same plane. Similar to an airplane propeller, they have blades that generate aerodynamic lift and pressurize the air. They can provide high airflow and are ideal for applications involving relatively low static pressure. 
• Centrifugal fans have air enter in one plane and exit in another. They have rotating impellers with blades that increase the speed of air streams and convert them into pressure. They can produce high pressures and are suitable for applications involving harsh conditions (e.g., moist or dirty air streams). 

Some of the factors to consider when selecting between these two fan designs are: 

• Pressure
• Airflow rate
• Efficiency rate
• Space constraints
• Noise generation
• Drive configuration
• Operating temperature range
• Operating environment range
• Cost
• Delivery time
• Availability

Step 4: Final Considerations 

In addition to the above, other considerations to keep in mind when choosing a cooling fan for a system include: 

• Integrating speed controls: Fans that run continuously at fast speeds will wear out quickly. Integrating speed control elements that alter the speed of the fan when needed can significantly increase the overall service life of a unit. 
• Incorporating performance monitoring circuits: Performance monitoring circuits track fan performance to identify potential malfunctions before they occur. 
• Establishing maintenance schedules/programs: Regardless of the fan you choose, it is essential to create and implement a maintenance schedule for it. Otherwise, the unit may break down unexpectedly. A basic maintenance program should cover the following: bearings, belts and sheaves, leakage, motor condition, and system cleaning. 

Quality Cooling Fans From Pelonis Technologies, Inc. (PTI)

Need additional assistance selecting a cooling fan for your application? Ask the experts at PTI! At Pelonis Technologies, Inc., we have developed and manufactured specialty cooling products for commercial and industrial operations for over 25 years. We have the knowledge and skills to answer any questions you may have and find the product that suits your exact needs. Contact us today to get started on your solution.

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Adding intelligent motion controls (IMC) to your fan or blower design can maximize your system’s performance. There are several types of IMC solutions available to add functionality to your fans and blowers. Four of the solutions include a rotation detector, life detection, DC voltage signal control, and current source signal control. In this post, we will discuss each of these solutions.

Solutions

Rotation Detector (Complement)

The rotation detector (complement) (RDb) control is an open collector with hardware similar to the frequency generator (tachometer) (FG) control #2a. The output signal is HIGH when the fan is rotating, but when the fan is stopped or powered OFF the output signal is set to LOW. The output can be connected in parallel to the RDb of a series of fans that end at a single alarm device, which provide a warning if any single fan has stopped working. The RDb control is an external violet wire.

Life Detection

Similar to the RDb, the life detection (LD) control is also an open collector with the same hardware as the FG control #2a. The output signal is HIGH under the fan’s normal rotation, and it is set to LOW when the fan’s rotation speed is below 70% of the device’s rated target speed. Slow rotation may be a sign of aging or wear of the fan or blower, or it could mean there is reduced power supply voltage. The LD control is a brown external wire.

DC Voltage Signal Control

The DC voltage signal (VPWM) control adjusts speed by applying an external DC voltage signal. The voltage input “Vin” can have a value ranging from 1V to 20V, with standard values of 1V to 5V. The fan speed varies linearly, is proportional to the percentage change of the “Vin” value, and corresponds to the same percentage change of the maximum speed. The constant speed (CS), inrush current protection (IR), and current limit (CL) controls are included.

The part number is followed by an additional identification entry, such as V 1 5 20 100 C 500. That number indicates that the fan speed is 1000 RPM (20%) at 1V and 5000 RPM (100%) at 5V. Additionally, the fan maintains the minimum speed if Vin is less than 1V and it stops if Vin is less than 0.5V (Mode “C” operation). The maximum fan speed is 5000 RPM, with a stop point typically set at 20% of the maximum. The VPWM control is an external white wire.

Current Source Signal Control

The current source signal (IPWM) control adjusts speed through the application of an external current source signal. The current input “Iin” may have values ranging from 4mA to 50mA, with standard values of 4mA to 20mA. The fan speed varies linearly, is proportional to the percentage change of the Iin value, and corresponds to the same percentage change of the maximum speed. The constant speed (CS), inrush current protection (IR), and current limit (CL) controls are included.

The part number is again followed by an additional identification entry, such as I 4 20 20 100 A 500. That number indicates the fan speed will be 1000 RPM (20%) at 4mA and 5000 RPM (100%) at 20mA. The fan maintains the minimum speed if Iin is less than 4mA (Mode “A” operation). The maximum fan speed is 5000 RPM, and the IPWM control is an external white wire.

Discover the IMC Solution That’s Best for You

Pelonis Technologies will help you find the perfect IMC solution to your fan or blower designs. We offer rotation detector, life detection, DC voltage signal control, and current source signal control. Learn more about our products and services on our website, where you can also contact us or request a quote.

 

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The direct current fans, or DC fans, are powered with a potential of fixed value such as the voltage of a battery. Typical voltage values for DC fans are, 5V, 12V, 24V and 48V.

In contrast, the alternating current fans, or AC fans, are powered with a changing voltage of positive and of equal negative value. In general, this changing voltage has sinusoidal shape. Worldwide, the usual value of this sinusoidal voltage may vary in size and in frequency, such as 100VAC, 120VAC, 200VAC, 220VAC, 230VAC or 240VAC, and with frequency (cycles per second) of 50Hz or 60Hz.  

In the past, big AC fans were typically less expensive compared to big DC fans. Today however, their price difference is negligible due to their payback advantage. We will try to point out differences between the above fan types, to help you choose and purchase the correct fan type for your application.

The Pros and Cons of DC fans

DC technology has become much more sophisticated in recent years, and it can now be applied to both residential and industrial ceiling fans. DC fans have motors that rely on permanent magnets in order to attract and repel a rotor around the axis using electronic switching. DC technology is much newer than AC technology, which means there are fewer options available.

PRO: Consumes less power

DC fans are widely regarded as the most efficient type of fans. They consume significantly less power than AC fans. In fact, DC fans consume up to 70 percent less energy to produce the same output as traditional AC fan types.

This means, that a 25-watt DC-driven yields the same results as 100-watt AC fan. This is ideal for commercial settings, like restaurants, allowing you to keep fans running all day without incurring astronomical electric bills.

PRO: Minimal electromagnetic interference

Due to low power used as well as the application of sophisticated electronic switching, the electromagnetic interference of DC fans is minimal. Sensitive electronic devices often use DC fans to prevent electromagnetic interference.

For example, computer applications and equipment rely on DC fans, to prevent overheating while still minimizing electromagnetic interference that could negatively affect sensitive applications.

PRO: Acoustically Quieter

DC fans make use of a new type (sin180) of electronically commutated motor (ECM). Not only are these motors ultra-efficient, they are also incredibly quiet. Because they are so quiet, DC fans are an excellent option for applications such as medical instruments, telecom switches, or car entertainment systems, where noise could be a nuisance.

PRO: Lower voltage

DC fans generally use less voltage than AC fans. The majority of DC fans are low-voltage fans. For example, you can typically find 5V, 12V, and 24V versions of DC fans. Larger models of DC fans, such as 119mm to 172mm fan models, are typically available in 48V. In comparison, most AC cooling fan models are available in 115V, a much higher voltage. Lower voltage also makes DC fans potentially less dangerous.

PRO: Water-Resistant

The DC fans can be used in applications of severe environmental conditions. It is imperative to employ a reliable, high-quality water-resistant model to ensure the safety of your equipment and staff.

Read More: Water-Resistant DC Fans for Harsh Environments

Pelonis Technologies, Inc. (PTI) has been designing, developing, and manufacturing industry-leading AC axial fans and brushless DC fans for more than 25 years. This includes a wide range of severe weather and water-resistant fans, which offer unparalleled dust and water protection while meeting military and NASA material specifications, USP certifications, and UL certifications.

Our harsh weather fans feature an eco-friendly proprietary conformal coating with excellent properties and corrosion resistance, allowing the fans to easily withstand dust, moisture, water exposure, and even full water immersion. Our DC fans also undergo a rigorous vacuum sealing process, enabling them to operate during submersion.

PRO: Intelligent Motion Control

The use of Intelligent Motion Controls in select model DC brushless fans and blowers has already arrived. With Intelligent Motion Controls, the movement of air is now smarter. 

The inclusion of full-wave-in-board circuit design and multiple features leaves no doubt that intelligence has enhanced air movement.

PRO: Variable flow

With minimal additional cost, the DC fan can offer a variety of speed control functions, so that the fan can meet the airflow target of a given application. The fan can be controlled by:

• Voltage
• Current
• Temperature
• Resistance
• PWM signals

By controlling the fan speed according to what is needed, the life of the fan can be increased and its acoustical airflow noise can be kept to the minimum necessary.

CON: May require an AC to DC converter

The AC fans are powered by an alternating voltage source. The DC fans are powered by a constant voltage source. This means that, the DC fan must have an AC to DC converter, either externally or included internally in the DC fan to convert AC to DC Voltage to power the DC fan.

The Pros and Cons of AC fans

AC fans are commonly used because the AC outlets are readily available in our houses.

CON: Variable flow

The speed control of the AC Fans is not easy matter. The AC fan’s speed depends on the line frequency and partially on the amplitude of the AC Voltage source.

To change the frequency of the AC Voltage is totally not practical due to its very high conversion cost. To vary the amplitude and maintain the waveform of the AC Voltage source is also expensive and certainly not practical to meet the target cost of a speed-controlled AC fan.

Less expensive “Capacitor” speed control methods, influence the power factor of the fan. Finally, economical “Phase Control” speed control methods introduce electromagnetic noise.

CON: More energy consumption

AC fans do consume more energy than DC fans. You need up to $3 worth of electricity using a DC Fan and you need $10 worth using an AC Fan to achieve the same airflow result.

CON: More electromagnetic interference

AC fans have more electromagnetic interference than DC fans, when they use “Phase Control” speed control methods.

AC vs. DC: Which Fan Is Right for You?

 

The bottom line is that the right fan for you will depend on your specific needs. Prior to deciding between an AC and DC fan, you will need to carefully weigh the pros and cons of each type of fan.

Pelonis Technologies offers fan technologies for a variety of industries and applications. To evaluate which one is right for you, view our guide on how to select the right cooling fan for you.

If you need further assistance in choosing the right fan for your project and/or application, don't hesitate to reach out the Pelonis Technologies team and we'll be more than happy to assist you!

 

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The Importance of Selecting the Right Cooling System

In the medical equipment industry, proper component functionality and performance is of utmost importance, as failures can cause dangerous malfunctions and delays that put patients at risk. When selecting a cooling system for your medical equipment application, it’s important to consider your project’s specific temperature and application needs. This will help to ensure longevity and reliability in your medical equipment.

AC Blowers in the Medical Industry

AC blowers — machines that provide air flow to facilitate various machine processes through the use of rotating blades — are often used in medical equipment to provide reliable, efficient air movement. For instance, AC blowers are utilized in medical and surgical beds to pump airflow up through mattresses, providing air circulation that prevents patients from experiencing pressure sores, skin shearing, hot flashes, and night sweats.

AC blowers can also have a great impact on the performance of thermal imaging systems, as many medical devices lose efficacy after critical temperature is reached, causing delays and added costs.

The Problem

Because medical device performance can suffer after reaching critical temperature, equipment such as MRIs, computed tomography (CT) devices, ultrasounds, and radiography (X-ray) machines are susceptible to subpar or slowed functioning. All of these devices rely on enclosure cooling to keep temperatures at optimal levels, as even slight fluctuations can affect performance. The FDA, however, helps maintain near-perfect (≥95%) repeatability and reproducibility of results in such equipment.

Because imaging technology designers generally have a narrow temperature range to work with, usually 50 ºF (10 ºC) between cabinet interior and exterior ambient temperature, cooling systems must be of the highest quality — dependable, quiet, and high performing, while also meeting the hygienic requirements of the medical industry.

The Solution

Typically used for sealed enclosures or devices, heat exchangers circulate hot air inside a device over an extended surface area, like internal fins, and circulate cooler external air over external fins. This keeps the interior temperature consistently warmer than the outside temperature.  If devices or enclosures are not sealed, however, small, silent, high-performing fans for medical equipment manufacturing can be used, which are less expensive and just as effective for non-sealed applications. Because most medical devices require sealing to maintain sanitation, heat exchangers are an ideal option to keep equipment functioning optimally and thereby reduce downtime and additional maintenance costs.

When incorporating a heat exchanger into medical equipment that requires a fan, be sure the power supply can accommodate the additional required power.

Cooling Solutions from Pelonis: The B1793 Blower

As a leading manufacturer of heating and cooling technologies, Pelonis is proud to offer a wide array of cooling options, including axial AC and brushless DC fans, as well as high-technology motors and OEM manufacturing solutions. Our B1793 TITAN AC blower, in particular, is ideal for use in the medical equipment industry.

With a patented engineered aluminum enclosure that acts as a heat sink, the B1793 is extremely heat resistant. This allows for cooler surface temperatures and reduced internal component wear. It also features an isolated open collector tachometer, which monitors running speed and locked rotor protection, ensuring automatic restart if the motor is released from a locked state. The B1793 blower also includes PWM operation that enables it to operate at various speed settings and it is a compact unit, allowing for easy installation and use in smaller medical devices.

To discuss how our cooling solutions can serve your application, or to learn more about fans, blowers, and heat exchanger components for the medical field, contact one of our in-house experts today, or download our AC blower catalog.

Axial vs Centrifugal Fans

There are two primary varieties of fan, axial fans and centrifugal fans. Pelonis Technologies, Inc. (PTI), a global leader in fan technology for more than 25 years, manufactures both axial and centrifugal fans.

To help clear up that confusion, here is a breakdown of the fan types, their benefits, and their uses.

The design and function of a centrifugal fan is very different from those of an axial fan. Their differences make them each suited for different applications and customers are sometimes unclear as to which fan type will best suit their needs.

Axial Fans

Axial fans date back to the horizontally configured windmills of Europe in the Middle Ages. The first electrically powered fans, introduced in the 1880s, were axial fans.

Axial fans are named for the direction of the airflow they create. Blades rotating around an axis draw air in parallel to that axis and force air out in the same direction.

Axial fans create airflow with a high flow rate, meaning they create a large volume of airflow. However, the airflows they create are of low pressure. They require a low power input for operation.

Centrifugal Fans

The centrifugal fan was invented in 1832 by military engineer Lieutenant General Alexander Sablukov of the Russian Empire’s Imperial Russian Army.

Often called blowers, centrifugal fans vary differently from axial fans. The pressure of an incoming airstream is increased by a fan wheel, a series of blades mounted on a circular hub. Centrifugal fans move air radially — the direction of the outward flowing air is changed, usually by 90°, from the direction of the incoming air.

The airflow created by centrifugal fans is directed through a system of ducts or tubes. This helps create a higher pressure airflow than axial fans. Despite a lower flow rate, centrifugal fans create a steadier flow of air than axial fans. Centrifugal fans also require a higher power input.

Fan Applications

Axial

Because of the low-pressure high-volume airflows they create, axial fans are best suited for general purpose applications. For example, they excel at moving air from one place to another, cooling confined spaces such as computers, and cooling larger spaces such as work spaces. 

A standard AC model is energy efficient, using no more than 100 watts when on high speed. AC fans can be connected directly to a DC power source, such as solar panels or batteries. Since the end goal in units like vending machines is an even flow of cooling power, an AC fan is the fairly obvious choice.

Currently, vending and refreshment industry leaders are trying to get the new generation excited about their services. As the new, hip crowd grows up attached to their technology, the industry is finding new and exciting ways to get their attention.

Cashless payment options, touch screens, and cell phone payment options are all becoming a part of the vending machine design. Companies like Intel® and Cisco Systems® are getting involved, which means the vending machine now has more and more in common with a computer.

And just like any computer you might have in your office, overheating becomes a larger concern with all this technology is included in the new designs.

With demanding technological features, you can see a drop-off in performance due to heat. AC fans are an excellent choice to maintain just the right amount of cooling for these components.

It’s for all these reasons, that we created the PM1225-7 series axial AC fan.  Axial AC fans are used extensively in vending machines to provide cooling where enclosure space is limited.

Centrifugal

Because of the high pressure they create, centrifugal fans are ideal for high pressure applications such as drying and air conditioning systems. As all of their moving parts are enclosed and they also have particulate reduction properties that makes them ideal for use in air pollution and filtration systems. Centrifugal fans also offer distinct benefits:

• First-rate energy efficiency. Constant airflow allows centrifugal fans to generate energy that reaches up to 84% static efficiency. These higher efficiency levels are ideal for sustaining larger air systems.

• Enhanced durability. These fans are durable enough to properly operate in the most corrosive and erosive environments.

• Ability to restrict overloading. Certain centrifugal fans are fitted with non-overloading horsepower curves will ensure the motor will not overload if its capacity is exceeded.

• Easy to maintain. Lighter material fans can be easily cleaned when you deem it necessary. Moreover, certain fans have self-cleaning characteristics, making daily maintenance that much easier.

• High versatility. Centrifugal fans are useful for multiple airflow/pressure combinations, and they can process several airflow conditions, including clean, dry, and wet air

• Multiple sizes. These fans are available in several sizes to accommodate diverse applications—such as those found in tight spaces or difficult to reach areas.

Learn More

Even within the categories of axial or centrifugal fans, there is a great amount of variation between models, all suited for different uses.

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As summer’s temperatures reach their peak, keeping your facilities cool is important for maintaining comfortable working conditions. Cooling commercial spaces properly means finding the right balance for employee comfort, temperature/humidity control, and energy use. In manufacturing operations where additional heat is generated by machinery, and in warehouses where goods must be stored in constant environmental conditions, cooling systems are vital mechanisms.

Optimizing Cooling Systems

Although summer is in full swing, it’s not too late to take steps to make sure HVAC systems are running efficiently. By optimizing cooling systems, energy consumption is reduced. Bringing down utility costs makes for a more sustainable and green environment. HVAC systems basically consist of condensers, fans, and thermostats and all must be in good working order to perform optimally. If any part is failing, your facility or warehouse may be uncomfortably hot.

Cooling Systems Maintenance: What Needs to be Done

To be sure your system is performing at its best, take the time to perform some basic preventative maintenance:

• System checks: Ensuring that all parts of the cooling system are working to peak performance begins with regular inspections. Performing regular checkups and inspections keep the system working well and will help you find potential problems before they cause a serious breakdown.
• Sensors and thermostats: As the brains behind the mechanics, sensors and thermostats must be working properly to maintain accurate indoor temperatures. Calibrate the instruments to ensure the temperature readings are correct and make sure they respond accurately to rising and falling temperatures.
• Filters and external equipment: Staying on top of filters and changing them regularly helps cooling units work efficiently and keeps the air as clean as possible. Check external units for dirt, debris, or damage from environmental conditions that could prevent the units from running smoothly.

How to Select a Cooling Fan

When choosing cooling equipment, look for the highest quality components. Since fans are integral components for all cooling systems it is important that this component be well made, durable, and reliable. If fans are improperly sized or inefficiently designed, the cooling system will not be able to maintain optimal temperatures.

It is often difficult to know if you are choosing the right fan for a specific application. To choose the fan that will meet performance specifications we have developed an eBook titled “How to Select a Cooling Fan.” This informational guide will help you choose a cooling solution that meets the needs of your operation.

As the leader in manufacturing high-quality AC and DC fans, PTI has the expertise to provide information on how to achieve the ideal temperatures in your facility. With a wide range of sizes available, we also have custom capabilities to meet the specific requirements. Our innovative technologies provide the right solutions for numerous industrial applications.

 

 

For more than 25 years, Pelonis Technologies has been a leader in supplying cooling and heating elements for industrial and commercial applications. In the pursuit of innovation, we regularly add new, high-quality products to our already substantial range of fully customizable fans, blowers, heaters, and accessories.