new 1pcs XFAN Fan 12CM 2 wire cooling fan RDM1238B DC12V 0.40A 12038

Engineer's Quick Brief

• Standardized 12038 Form Factor: Measures exactly 120mm x 120mm x 38mm, making it a universal drop-in replacement for thick-frame, high-static-pressure cooling applications in industrial chassis and equipment.
• Direct 2-Wire Operation: Simple and robust 2-wire design (Positive/Negative) running on standard 12V DC at a highly efficient 0.40A draw, ensuring direct-to-power reliability without complex PWM controllers.
• Continuous Duty Ready: The "B" designation in RDM1238B typically denotes a Ball Bearing system, superior to standard sleeve bearings for high-temperature environments, horizontal mounting, and continuous 24/7 operation.

SEO Introduction

The XFAN RDM1238B is a heavy-duty, industrial-grade DC Axial Cooling Fan designed for rigorous thermal management. Utilizing the industry-standard 12038 size profile (120 x 120 x 38 mm), this 38mm thick frame provides significantly higher static pressure and air volume compared to standard 25mm thick PC fans. Operating efficiently on a 12V DC supply with a current draw of exactly 0.40A, it strikes an optimal balance between aggressive heat evacuation and energy efficiency. Configured with a straightforward 2-wire lead setup (Red for Vcc, Black for Ground), it is engineered for "always-on" direct drive applications, eliminating points of failure associated with complex tachometer or PWM circuits. It is an essential replacement component for variable frequency drives (VFDs), welding machines, telecom cabinets, and legacy server enclosures.

Technical Specifications

Application Matrix

• Industrial VFDs & Inverters: Essential for evacuating dense heat generated by high-power IGBT modules within automated motor control cabinets.
• Welding Equipment: Withstands the harsh, dust-heavy environments of fabrication shops, keeping internal transformers and rectifiers within safe thermal limits.
• Telecommunications & Networking: The 38mm thick frame generates the high static pressure necessary to push cooling air through densely packed relay racks and power supply units (PSUs).
• Cryptocurrency Mining & Server Racks: Serves as a reliable, high-uptime exhaust fan where continuous 100% duty cycle operation is mandatory.

Troubleshooting & FAQ

• Can I connect this 2-wire fan to a 3-pin or 4-pin motherboard header? Yes. A 2-wire fan can be plugged into a 3-pin or 4-pin header. You must align the Black wire with the Ground (GND) pin and the Red wire with the 12V pin. However, because it lacks a tachometer (yellow wire) and PWM control (blue wire), the motherboard cannot read its RPM, and the fan will run continuously at 100% maximum speed.
• The fan is not spinning when powered on. What should I check? First, verify the polarity; DC fans are highly polarity-sensitive. Ensure Red is connected to +12V and Black is to Ground. Second, use a multimeter to confirm the power supply is actually delivering 12V DC. If polarity and voltage are correct but the fan is dead, the internal motor coil is likely burnt out.
• Can I run this 12V fan on a 24V industrial power supply? No. Supplying 24V to a fan rated strictly for 12V DC will cause the internal coils to overheat rapidly, resulting in catastrophic motor failure, melting, and potential fire hazard. Always use a step-down buck converter if only 24V is available.
• Why is the fan vibrating loudly or making a grinding noise? Loud grinding or heavy vibration typically indicates that the internal ball bearings have reached the end of their service life, or that physical debris has unbalanced the impeller blades. To prevent damage to the equipment chassis from resonant vibration, the fan should be replaced immediately.

Cross-Reference Guide

The 120x120x38mm form factor is an industry standard. If the XFAN RDM1238B is unavailable, it can be seamlessly substituted with other major brands, provided you match the 12V DC voltage and approximate the 0.40A current draw to ensure similar airflow performance:

• Delta Electronics: AFB1212 / FFB1212 Series (Ensure you select a variant close to 0.40A; Delta often makes much higher amperage server fans that will be significantly louder).
• Sunon: EEC0381B1 / MEC0381V1 Series (12038, 12V, Ball Bearing).
• Nidec / Sanyo Denki: Look for their standard 120x120x38mm, 12V DC, 2-wire configurations.
• Important Note: When swapping brands, always reuse your original connector plug if the new fan comes with bare leads. Simply splice and heat-shrink the Red to Red, and Black to Black.