6SE6440-2UD31-8DA1 Variable Frequency Drive MicroMaster 440 18.5kW 3-ф/380

6SE6440-2UD31-8DA1 — a Siemens MICROMASTER 440 rated 18.5 kW, three-phase 380 V supply, rated current 38 A. Remember: the series is discontinued — this model is bought to replace the same drive on a running line, not for a new project.

Typical applications:

• High-power water-utility pumping stations
• Industrial compressors and fans
• Extruders and process lines

Note: A three-phase 380 V model, the standard for industrial sites. Vector control and a built-in braking chopper make it suitable for dynamic loads too, not only pumps. If this exact part number is out of stock, we will suggest a current equivalent — a Siemens SINAMICS G120 or a budget Veichi AC310.

Siemens MICROMASTER 440 — a vector drive for like-for-like replacement on a running line

Let's be upfront: the MICROMASTER 440 (6SE6440 series) is a discontinued drive. Siemens has ended production and officially moved customers to the SINAMICS G120 / G120C family. So we keep MM440 not for new projects, but for plants where exactly this drive has failed on running equipment and a one-for-one replacement is needed — no rewiring of the cabinet, no PLC program changes.

In its day the 440 was the flagship of the MICROMASTER family (the 420 was the basic V/f unit, the 440 the vector model for demanding tasks). Our stock range: 0.7 to 55 kW, single-phase 220 V input models and three-phase 380 V models.

What the MM440 could do

• Sensorless vector control and FCC: holds torque at low speed without an encoder — real control, not just V/f for a fan.
• Built-in braking chopper: in most frame sizes the brake module is already inside; you only add an external resistor.
• Overload 150% for 60 s and 200% for 3 s: survives hard starts and load peaks.
• BICO and free function blocks: simple local logic right in the drive, no separate controller.
• Modular fieldbus: detachable operator panel and optional modules (historically PROFIBUS) for integration into Siemens lines.

MM440 versus the alternatives

If the drive is still alive but you are planning a refit, note that the G120C in the FSAA frame is footprint-compatible with the MM420/MM440, so the move to a modern Siemens drive is about as painless as it gets.

When the MICROMASTER 440 is NOT the right choice

• A brand-new project where you need warranty and current firmware — choose the SINAMICS G120/G120C.
• A tight budget with no tie to Siemens PLCs — look at our frequency inverters Veichi AC310 or the compact AC10.

Our experience

Most MM440 enquiries come from maintenance teams who need to keep a line running right now. We help match the exact 6SE6440 part number and, where it makes sense, we will honestly tell you when moving to a G120 or a budget Veichi beats hunting down a rare discontinued frame size.