In general, AC cooling fans have motors that use higher voltage than DC cooling fans, so the AC models are often used to produce high pressure air currents in systems that will not malfunction because of the fan’s electromagnetic interference. Most DC cooling fans operate at low voltage. You can generally find 5V, 12V and 24V versions; and in larger sizes, from 119mm to 172mm, in 48V. In comparison, 115V is one of the most common AC cooling fan models.
All types of computer equipment rely on DC cooling fans to prevent them from overheating. This includes everything from large servers to home PCs. The advantage of DC cooling fans is that they create less electromagnetic interference. This enables them to cool computer systems without disturbing processes with electromagnetic interference.
When choosing DC cooling fans for your computer, you might find that some of them are rated as 48VDC instead of 5V, 12V, or 24V. This is perfectly normal. VCD is simply another way of stating the amount of voltage that the fan uses. While the DC and VCD differentiation makes no difference, you should be certain to choose brushless models for your computer cooling needs.
Always use caution when installing AC or DC cooling fans. It is best to make sure that any equipment is unplugged before attempting to install fans. Both DC and AC currents can cause serious damage to humans when delivered in powerful doses. Even though most modern home electrical systems will not deliver a deadly jolt, a slight slip could still cause significant pain or even tissue damage.