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.
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.
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:
- PWM signals
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.
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!