Siemens Inverter 6SE6440-2UD25-5CA1 6SE64402UD255CA1 Siemens Frequency Converter 6SE644O-2UD25-5CA1

6SE6440-2UD25-5CA1 | Siemens MICROMASTER 440 Inverter — 5.5kW / 7.5kW / 380–480V AC / Frame C / Without Filter / IP20

MICROMASTER 440 — FANUC's High-Performance VFD

The MICROMASTER 440 is Siemens' highest-specification MICROMASTER series inverter — offering advanced motor control capabilities that go beyond simple V/Hz speed regulation. The 6SE6440-2UD25-5CA1 covers two power ratings depending on the application's overload profile:

5.5kW constant torque (CT / High Overload, HO): For applications requiring sustained torque at all speeds — conveyor drives, hoists, compressors, and machine tools where full torque must be available from low speed to high speed without overload limitations.

7.5kW squared torque (LO / Fan-Pump): For fans, pumps, and centrifugal compressors where torque demand reduces with the square of speed — allowing the same drive to power a larger motor in lower-overload applications.

Key Specifications

Without Filter — EMC Planning Required

The 6SE6440-2UD25-5CA1 is supplied without an internal EMC filter. For installations requiring compliance with European EMC emission standards (EN 61800-3 Category C1 or C2), an external EMC filter must be fitted on the drive's mains input. Siemens offers purpose-designed external filter options for the FSC Frame C MM440 — confirm the required filter class from the installation's EMC assessment.

Application Scenarios

Machine tool main spindle drive: A machining centre requires variable speed spindle control up to 24,000 rpm — needing approximately 400Hz output. The 6SE6440-2UD25-5CA1 provides full-range speed control with FCC vector mode for smooth torque at all spindle speeds.

Conveyor and packaging machine: A production line conveyor requires reliable variable speed control with sensorless vector mode — the 6SE6440-2UD25-5CA1 provides precise speed regulation regardless of varying product load across the belt.

FAQ

Q1: What is the difference between the CT (5.5kW) and LO (7.5kW) ratings on 6SE6440-2UD25-5CA1?

CT (Constant Torque / HO) 5.5kW: the drive can provide 150% of rated current for 60 seconds and 200% for 3 seconds — for applications needing high transient torque. LO (Low Overload / Fan-Pump) 7.5kW: reduces the overload headroom to 110% for 60 seconds and 140% for 3 seconds, but allows a larger motor to be connected for fan and pump loads where transient torque is not required. Select based on the application's overload duty.

Q2: Does 6SE6440-2UD25-5CA1 include an operator panel?

No — this variant is supplied without AOP (Advanced Operator Panel) or BOP (Basic Operator Panel). Without an operator panel, the drive can still be operated from the terminal strip (analogue/digital inputs) or via RS485 serial communication. For local parameter access and display, a BOP-2 or AOP-2 panel must be ordered and fitted separately.

Q3: What serial communication protocol does 6SE6440-2UD25-5CA1 support natively?

The MM440 includes an integrated RS485 port supporting the USS (Universal Serial Interface) protocol — a Siemens serial protocol for drive communication without requiring a separate PROFIBUS or other fieldbus option module. For PROFIBUS DP connectivity, a CBP2 communication board can be fitted in the MM440's option slot.

Q4: What braking options are available for 6SE6440-2UD25-5CA1?

The MM440 does not include a built-in braking resistor but supports connection of an external braking resistor through a minimum 56 Ω external resistor — providing dynamic braking for applications requiring controlled deceleration of high-inertia loads. For higher-duty braking, external braking modules can be connected to the DC bus link.

Q5: What are the ambient temperature limits for 6SE6440-2UD25-5CA1?

The 6SE6440-2UD25-5CA1 is rated for ambient temperatures from −10°C to +50°C without derating. Operation above +50°C requires output current derating. Storage is permitted from −40°C to +70°C. The IP20 enclosure requires the drive to be installed inside a suitable control cabinet when used in environments with access to conductive particles, water spray, or corrosive atmospheres.