Why Voltage Matters When Selecting a DC Cooling Fan
When engineers start a new design, they often have multiple DC voltage supply options such as 5, 12, 24, and/or 48VDC, and may wonder which DC fan to use.
Higher voltage DC cooling fans, particularly 48V models, offer significant advantages in applications requiring high power efficiency, reduced wiring complexity, and improved thermal management, making them ideal for telecom, data centers, and industrial systems.
As systems generate higher heat and require increased static pressure, 48V fans are increasingly chosen for servers and data centers where the power supply is standardized at 48V. Additionally, equipment with battery-powered operation (automobile, robots, etc.) tends to use 48V fans for greater efficiency.
This brief article will explain the Pros and Cons of higher voltage DC cooling fans, particularly 48V options, and help you select the best fan based on your available supply voltages.
Common DC Voltage Options and Their Applications
Here are the most common supply voltages and associated end applications.
| Voltage | Description |
|---|---|
|
5VDC |
Originally found in the computer desktop but still exists today in low-power applications such as sensors, microcontrollers, and communication devices. Recall the 5V output is a standard voltage for USB-powered devices. |
|
12VDC |
Used in many applications including automotive, industrial, security systems, LED lighting and telecom applications. |
|
24VDC |
Found in medical, industrial automation and control systems. |
|
48VDC |
Telecom/network applications that need high power like servers, switches found in data centers, etc. |
If your design allows for either 12V or 48V, which should you choose? Let’s break down the key differences.
Advantages of Higher Voltage DC Cooling Fans
So, for example, if 12V and 48V supply voltages are available for your new design, which voltage rated fan should you choose if they have equal CFM/static pressure specs?
If both 12V and 48V supply voltages are available for your design, which fan should you choose, assuming equal CFM/static pressure specifications?
If you look at the catalog snippet below, our 9HV 80x38mm series, the only difference would be the reduction in nominal rated current from 3.4 to 0.85A for the 12V and 48V DC fans respectively.
1. Lower Current Reduces PCB Trace Width & Connector Size
This advantage will become more apparent when you consider your connector/contact selection and trace widths on your PCB that supplies power to the fan as they can both be reduced in size.
2. Lower Startup Current Eases Power Supply Selection
Also the startup current for a higher voltage 48V cooling fan will be lower which may help with choosing your total system power supply.
See below link to the brief article of startup current for DC fans.
So, from the above catalog, after requesting the drawing of the 12V fan we see a startup current of 7A, while the drawing for the 48V fan shows a 2A startup current. If we consider the JST PH Connector Series, which is very popular based on its small size and current rating of 2A, it can be used with the 48V fan but not the 12V fan as its current rating of the connector would be violated.
3. Improved Wiring Efficiency and Reduced Heat
- Higher voltage DC cooling fans use thinner lead wires, reducing clutter and improving airflow.
In general, higher voltage DC cooling fans are more common in larger frame sizes and higher performance fans. This is because the usage of lower voltages in a fan as it increases in power and size, will require much thicker lead wire gauge and PCB traces to prevent damage of the electronics.
4. Better Suitability for Large, High-Performance Fans
- In many instances, using a 12V fan for high performance or large motor designs becomes difficult, requiring 24V or 48V instead.
- A higher voltage DC cooling fan helps maintain performance while keeping wire thickness manageable.
In many instances, the usage of 12V in a fan becomes difficult while still maintaining high performance or large size motor designs and thus 24V or 48V are required. Thicker wires in the stator (winding) of the fan motor are also needed for a lower voltage, equal performance fan, due to less efficient wire stacking and the larger bend radius (especially in the larger frame size fans).
Are There Any Downsides to Higher Voltage Fans?
While higher voltage fans offer many advantages, there are a few things to consider:
- Higher-rated electronic components
- Voltage restrictions in some industries
But the internal electronics of the fan cannot operate with a direct 24V or 48V supply so it needs to be stepped down to accommodate this and require higher voltage rated components. This results in a small price adder for the higher voltage options.
Also note that many medical applications require using a maximum of 24 VDC
How to Choose the Best DC Fan Voltage for Your Application
In closing, when selecting a fan besides the size, performance and acoustic noise requirements, the supply voltage should also be considered as follows:
1. Available Power Supply Options
- For the available DC power supply, do you have options?
- Can your power supply handle the startup current of the selected fan?
If so, do you have available power allocated for the specific fan voltage (keeping in mind that the startup current issue of the fan(s) needs to be considered)?
2. Safety and Compliance
- Are there specific voltage limitations for your industry?
- Medical applications often require 24V or lower.
Are there any safety and compliance requirements for your specific application?
3. Space-Saving Opportunities
Is the fan selection available in higher supply voltages? If so, you could take advantage of:
- Using the thinnest lead wire AWG of the fan making it easier to route the lead wires
- Reducing the trace widths on your PCB allowing easier layout
- Using smaller connectors that would save PCB board space
Depending on the fan series you choose, we often offer multiple voltage options. If a specific voltage variant is not listed, please contact your local SANYO DENKI representative to check availability.
Written by Gary Masessa
About SANYO DENKI
SANYO DENKI has been a trusted provider of cooling solutions for various industries, with fans being a crucial component in many advanced devices. Contact us for a quote, or to discuss your device's customization requirements.
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