ebm-papst is a well-known provider of many various types of cooling fan, including metal tubeaxial designs like DV6224. While this fan is obsolete, you can still find it in its DV6224/2 form, with an extra ‘/2’ suffix. What’s the difference between these two?
For this fan, the /2 indicates the addition of a speed sensor (tachometer) output not present in the original obsolete design. This allows the fan to incorporate speed sensing into the industrial solutions it’s aimed at, where such measurements are often critical. This can complicate matters for simpler systems that do not need the speed sensor and cannot easily handle having the third wire. For parametrically similar two-wire poutput aluminum-framed fans, you can check options here: 24VDC Aluminum Fans.