What is the difference between AC fans and DC fans?


Direct current fans (or DC fans) are powered by a potential of fixed voltage such as the voltage of a battery. The voltages for DC fans are typically 5V, 12V 24, 24V, 48V and 48V.

The alternating current fans (or AC fans) are powered by a changing voltage with equal positive and negative values. This changing voltage is generally sinusoidal in shape. The usual sinusoidal voltage value can vary worldwide in size and frequency. For example, 100VAC is 120VAC and 200VAC are all possible values. Also, there may be a variation in frequency (cycles per minute) of 50Hz and 60Hz.

In the past, AC fans were generally less expensive than DC fans. Their payback advantages make their cost difference negligible today. To help you select the right fan type for your application, we will highlight the differences among the fan types.

DC Fans: The Pros and Cons

DC fans: The pros and cons DC fans use permanent magnets to attract and repel the rotors around the axis. They also make use of electronic switching. DC technology is more advanced than AC technology. This means that there are fewer options.

PRO: Consumes less power

DC fans are generally regarded as being the most efficient type. They use significantly less power than AC fans. DC fans use up to 70% less energy than traditional AC fans to produce the same output.

A 25-watt DC-driven fan will produce the same results as a 100-watt AC fan. This makes it ideal for commercial environments, such as restaurants. It allows fans to run all day without paying astronomical electricity bills.

PRO: Minimal electromagnetic interference

The electromagnetic interference caused by DC fans is very low due to the use of low power and the application of sophisticated electronic switch technology. To prevent electromagnetic interference, sensitive electronic devices frequently use DC fans.

Computer equipment and applications rely on DC fans to keep them cool while minimizing electromagnetic interference which could adversely affect sensitive applications.

PRO: Acoustically Quieter

DC enthusiasts use a new type of electronically commutated motor, the sin180. These motors are extremely efficient and very quiet. DC fans are a great choice for applications like medical instruments, telecom switches or car entertainment systems where noise can be a problem.

PRO: Lower voltage

AC fans use more voltage than DC fans. Low-voltage DC fans make up the majority of DC enthusiasts. You can find DC fans in three voltages: 5V, 12V and 24V. The 48V voltage is often used for larger DC fans models (e.g. 119mm-172mm fan models). AC cooling fan models, on the other hand, are usually available in 115V. This is a higher voltage. DC fans are also less dangerous because they require lower voltage.

PRO: Water-Resistant

DC fans can be used under severe environmental conditions. To ensure safety for your staff and equipment, it is important to use a reliable, water-resistant model.

Learn More: Water-Resistant DC Fan for Harsh Environments

Pelonis Technologies, Inc. has been developing, designing, and manufacturing industry-leading AC fans and brushless DC fans since more than 25 year. These fans offer exceptional dust and water protection, while also meeting military and NASA material specifications, USP and UL certifications.

The eco-friendly conformal coating on our harsh weather fans is extremely durable and resistant to corrosion. It can withstand moisture, dust, water exposure and full immersion. The DC fans are also subject to a rigorous vacuum sealing procedure, which allows them to function even when submerged.

PRO: Intelligent Motion Control

Intelligent Motion Controls are now available in select models of DC brushless fans. Intelligent Motion Controls make air movement more intelligent.

Intelligence has facilitated air movement by incorporating full-wave-inboard circuit design and other features.

PRO: Variable flow

The DC fan offers a range of speed control functions at minimal cost. This allows the fan to meet the required airflow targets for a particular application. You can control the fan by:

  • Voltage
  • Current
  • Temperature
  • Resistance
  • PWM signals

You can increase the fan’s life by setting the speed to suit your needs. This will also reduce the noise from the acoustic airflow.

CON: You may need an AC to DC converter

AC fans are powered using an alternating voltage source. DC fans are powered from a constant voltage source. The DC fan must be equipped with an AC-DC converter. This can be either installed externally or internally. It converts AC Voltage into DC Voltage to power it.

AC Fans: The Pros and Con

AC fans are often used because AC outlets are easily accessible in our homes.

CON: Variable flow

ac-fanpelonisThe control of AC fans’ speed is difficult. AC fans’ speed is affected by the AC Voltage source and partly the frequency of the AC line.

Due to the high cost of conversion, it is impossible to change the AC Voltage frequency. It is very expensive to adjust the AC Voltage source’s amplitude or maintain its waveform. This makes it impossible to afford a speed-controlled AC fan.

The fan’s power factor can be affected by less expensive “Capacitor speed control” methods. The last option is to use “Phase Control”, which introduces electromagnetic noise.

CON: Increased energy consumption

AC fans consume more energy than DC Fans. To achieve the same airflow results, you will need to use up to $3 of electricity to run a DC fan. An AC fan requires $10.

CON: More electromagnetic interference

AC fans are more susceptible to electromagnetic interference than DC fans when they use “Phase Control speed control methods”.

AC vs. DC – Which fan is right for you?

Bottom line: The right fan will depend on what you need. Before you decide between an AC or DC fan, it is important to weigh the pros and cons.


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