POWER CONNECTOR 6FX2003-OLU00 6FX2 003-OLU00 6FX2OO3-OLUOO

Siemens 6FX2003-0LU00 | MOTION-CONNECT Size 1 Power Connector Kit — 6-Pole Socket, Screw Cap, 8 Socket Contacts 1–2.5mm², Dual Cable Terminations for Servo Motor Power Cables

Part Number: 6FX2003-0LU00

Manufacturer: Siemens AG (Slovakia)

Product Line: MOTION-CONNECT — Servo Cable Accessories

Product Type: Power connector kit — field-assembly (6-pole, socket side, screw cap)

Pole Count: 6

Kit Contents:

• 1 × 6-pole insulator housing (socket / female side)
• 8 × socket contacts, wire range 1–2.5 mm²
• 1 × cable strain relief termination, cable diameter 7.5–12mm
• 1 × cable strain relief termination, cable diameter 9–15mm

Overview

The Siemens 6FX2003-0LU00 is the Size 1 power connector socket kit from MOTION-CONNECT — the assembly hardware for the female end of a 6-pole servo motor power cable.

In Siemens servo drive installations, every motor needs a power cable running from the drive's power output to the motor's power input, and that cable terminates in a connector at the motor end. This is that connector — or rather, the components to build it.

The 6-pole arrangement covers the standard servo motor power wiring: three phases (U, V, W) for the motor windings, a protective earth conductor, and two brake conductors for motors equipped with a holding brake.

That is six conductors — six poles — which is why this connector size appears consistently across the SINUMERIK/SINAMICS ecosystem wherever a servo motor with an integrated brake needs a power connection.

Motors without brakes use fewer than six poles but may still use a 6-pole connector with brake positions unpopulated, maintaining connector interchangeability across motor variants on the same machine.

The socket (female) orientation of the 6FX2003-0LU00 — housing with female contacts, secured by a screw cap that threads onto the mating male connector on the motor housing — defines its role in the cable assembly: this end goes at the cable, the mating male connector (6FX2003-0LA00 or equivalent) goes at the fixed device. When connected, the screw cap locks the assembly mechanically, maintaining vibration resistance and preventing accidental disconnection during machine operation.

The screw-cap locking mechanism is the distinguishing feature of the -0LU00 variant compared to alternatives that use bayonet or push-pull locking. Screw locks provide higher pull-out force, are less susceptible to vibration-induced release, and are more tamper-evident — the cap must be visibly rotated to connect or disconnect.

For machine tool installations where motor connectors are subject to continuous vibration during cutting operations, the screw cap's mechanical security is a practical maintenance advantage.

Key Specifications

Size 1 in the MOTION-CONNECT Power Connector Family

The MOTION-CONNECT power connector system uses a size designation (Size 1, Size 1.5, Size 2, Size 3) that corresponds to the current-carrying capacity of the connector and the cross-section range of the contacts.

Size 1 — to which the 6FX2003-0LU00 belongs — is the smallest and handles conductors from 1 to 2.5 mm², suitable for servo motor power cables in the lower to mid power range. 

A 1mm² copper conductor at 24°C ambient and appropriate thermal conditions carries approximately 13–17A; a 2.5mm² conductor handles approximately 20–26A depending on installation method and bundling.

This places Size 1 connectors in the territory of servo axes from a few hundred watts up to several kilowatts, depending on the supply voltage and the cable's continuous current rating.

The kit includes eight socket contacts rather than exactly six — the extra contacts provide replacements if a contact is damaged during assembly (contacts can be damaged by incorrect crimping technique or by re-working a previously assembled cable), and they accommodate future assembly needs from the same kit.

Eight contacts provide two spares above the six required for a 6-pole cable, covering most assembly situations without requiring a second kit purchase.

Two Cable Strain Relief Terminations — Why Both Are Needed

A servo motor power cable does not have a fixed outer diameter — different cross-sectional areas and shield constructions produce different overall cable diameters.

A 4×1.5mm² motor cable with a thin braid shield might have an outer diameter of 8mm; the same cable in 4×2.5mm² with a robust rubber jacket might be 12mm or more. 

Both must mate with the same 6-pole connector housing, which is why the 6FX2003-0LU00 kit includes two strain relief terminations covering different diameter ranges:

The 7.5–12mm termination fits standard single-axis motor power cables in the Size 1 current range — the majority of SINUMERIK machine tool axis cables.

The 9–15mm termination accommodates heavier cables — those with additional conductors (combined power + brake cables in a single jacket), cables with particularly heavy shields or armour, or cables where the manufacturing tolerances result in a larger outer diameter.

The engineer selects the appropriate termination at assembly time and stores the unused one for future use.

This dual-termination approach means one kit covers two cable diameter ranges without the engineer needing to identify in advance which exact cable diameter will be installed.

Screw Connection — Assembly Technique

The screw connection (Schraubanschluss) method in the 6FX2003-0LU00 differs from crimp contacts used in some connector families. Each socket contact contains a captive screw that clamps the stripped conductor end when tightened.

The conductor is inserted into the contact's wire entry hole and the screw is tightened to the specified torque — no crimp tool is required for conductor termination, only a small screwdriver.

This screw-termination approach has specific advantages for field repair situations: it does not require keeping specialised crimp tools available at the machine, contacts can be re-terminated if the initial connection is incorrect (the screw is simply loosened, the conductor withdrawn, re-stripped if necessary, and re-inserted), and the connection quality can be verified visually by checking screw tightness rather than inspecting a crimp profile.

The recommended torque for 1–2.5mm² screw contacts is specified in the MOTION-CONNECT assembly documentation.

Undertightening leaves a high-resistance connection that generates heat under motor load current; overtightening risks fracturing fine-stranded conductors.

FAQ

Q1: The kit contains 8 socket contacts for a 6-pole connector. Are all 8 contacts used?

A 6-pole connector requires exactly 6 contacts — one per pole. The kit's 8 contacts provide 2 spare contacts above the minimum requirement, accommodating accidental damage to a contact during assembly or providing replacement contacts for future re-use of the same kit.

The 2 spare contacts are simply stored unused. Contacts should not be inserted into unused poles of the 6-pole housing unless specifically required by the cable design.

Q2: What is the mating connector — the male pin connector — that connects with this socket?

The mating connector for the 6FX2003-0LU00 socket is the 6FX2003-0LA00 — the Size 1, 6-pole pin connector with male thread that typically mounts on the servo motor's terminal box or drive module's power output connector.

The 6FX2003-0LU00 socket's screw cap threads onto the 6FX2003-0LA00 male housing to lock the mated pair.

When ordering a replacement cable connector kit, both the socket end (this part, on the cable side) and the pin end (motor or drive side) may be needed.

Q3: Can this connector be used on the drive amplifier side, or only on the motor side?

The MOTION-CONNECT convention assigns socket connectors to the cable side and pin connectors to the fixed device (motor or drive) side.

However, the physical connector family is symmetrical — any Size 1 socket can mate with any Size 1 pin, regardless of which end they are used on, as long as the pole count matches. 

In practice, the assignment is determined by what connectors are already installed on the motor and drive — the cable kit matches those interfaces. 

Most Siemens servo motors use male pin connectors at the motor end, making the socket end (this part) the cable-side connector.

Q4: Is this kit compatible with the SPEED-CONNECT version of MOTION-CONNECT connectors?

The standard 6FX2003-0LU00 (screw cap) and the SPEED-CONNECT variant (6FX2003-0LU30, if available) use different locking mechanisms and are not interchangeable with respect to the locking feature. The SPEED-CONNECT system uses a quick-lock mechanism for faster assembly and disassembly without rotating a screw cap.

The insulator housing and contact dimensions within the same size class are the same, but the locking collar differs.

Check the specific motor and drive connector types installed on the machine to confirm which locking mechanism is fitted before ordering the cable-side connector kit.

Q5: How should the shield of the motor power cable be handled with this connector?

Servo motor power cables are shielded to contain the high-frequency switching noise generated by the drive's PWM output.

The shield must be properly terminated at both ends — typically at the drive's PE terminal and at the motor connector's metallic housing.

The 6FX2003-0LU00's metallic screw cap and housing provide a shield termination point; the cable braid is folded back over the cable jacket within the strain relief and clamped against the connector housing when the strain relief termination is tightened. 

This 360° shield contact at the connector provides the low-impedance earth path required to prevent radiated EMI from the cable affecting nearby sensors or signal wiring.