KUKA 1FK7101-5AY71-1SY3-Z Replacement Servo Motor C26D00

Product Overview

KUKA 1FK7101-5AY71-1SY3-Z Replacement Servo Motor C26D00: Smooth Transition from Legacy KUKA Robot Axis Drives

When a KUKA robot axis drive fails or a legacy servo motor reaches end-of-life, unplanned downtime can cost thousands of dollars per hour on the production floor. The KUKA C26D00-100-782KCP2 / 1FK7101-5AY71-1SY3-Z S77 Servo Motor (4.9 kW) is a direct-fit replacement engineered for seamless integration into existing KUKA robot systems — including KRC2 and KRC4 controller architectures — without requiring mechanical rework, rewiring, or software re-parameterization beyond standard axis commissioning.

This unit belongs to the Siemens SIMOTICS S-1FK7 series, the OEM-specified servo motor family used across KUKA KR 6, KR 16, KR 30, KR 60, and KR 100 robot platforms. Whether you are replacing a worn axis 1–6 motor on a KR 16-2 or upgrading a decommissioned KRC2-era robot to extend its service life, this motor delivers the rated torque, encoder resolution, and mechanical interface required for a plug-and-play swap.

Compatibility Comparison Table

Seamless Upgrade Solutions

A successful servo motor replacement on a KUKA robot rarely involves the motor alone. During the swap, experienced maintenance engineers typically inspect and, where necessary, replace adjacent components to ensure the entire axis drive chain is restored to full specification. When replacing the 1FK7101-5AY71-1SY3-Z on axis 1 or axis 2 of a KR 30 or KR 60 platform, it is common practice to simultaneously verify the condition of the SINAMICS S120 Motor Module (e.g., 6SL3120-1TE21-8AA3) that drives this motor, since a failing motor can sometimes cause overcurrent faults that stress the associated power electronics.

The DRIVE-CLiQ encoder cable connecting the motor to the S120 Motor Module should be inspected for insulation damage and connector wear — a degraded cable can cause encoder communication errors (F07801/F07802) that mimic motor faults. Similarly, the motor power cable with M23 circular connector should be checked for continuity and shielding integrity before the new motor is commissioned.

If the robot is running on a KRC2 controller with an older KUKA KPS 600 power supply unit, this is an ideal time to assess whether the KPS 600 capacitors are within service life — a degraded power supply can cause undervoltage trips on the newly installed motor during high-load cycles. For KRC4-based systems, the KPP 600-20 KUKA Power Pack and associated KSP 600-3×40 servo pack modules should be confirmed as fault-free before axis re-referencing.

On the mechanical side, the KUKA axis gearbox (e.g., Harmonic Drive or planetary gearbox on axis 1–3) should be inspected for backlash and lubrication condition during the motor removal process, since the gearbox and motor share the same mounting interface. Replacing the motor without servicing a worn gearbox can result in premature re-failure. Additionally, the brake resistor module within the KRC2/KRC4 cabinet should be verified for correct resistance and thermal condition, as regenerative braking loads from a high-inertia axis can degrade resistors over time.

For facilities managing a fleet of KUKA robots, it is advisable to maintain a small buffer stock of 1FK7 series servo motors across the common axis ratings — including the 1FK7060-5AF71 (axis 4–6 range) and 1FK7080-5AF71 (mid-range axis) — alongside spare SINAMICS S120 Booksize Motor Modules and DRIVE-CLiQ hub modules (DMC20) to minimize mean time to repair (MTTR) across the production line.

Retrofit Guidance FAQ

Q: Do I need to re-parameterize the SINAMICS S120 drive after installing this replacement motor?
A: In most cases, no full re-parameterization is required. Because this is a 1:1 OEM-equivalent replacement with the same DRIVE-CLiQ encoder, the S120 Motor Module will automatically read the motor nameplate data via the encoder EEPROM on first power-up. You will need to perform a KUKA axis mastering (referencing) procedure using the EMT (Electronic Mastering Tool) or a dial gauge on the mastering notch, as the absolute encoder position is reset when the motor is physically removed.

Q: Is the wiring harness from the old motor reusable?
A: Yes. The M23 circular power connector and the DRIVE-CLiQ encoder connector are identical between the outgoing and replacement unit. No adapter or pin-out modification is required. Inspect the cable for abrasion damage at the cable entry point before reuse.

Q: Will this motor fit in the same physical space as the original?
A: Yes. The 1FK7101 frame size and IM B5 flange dimensions are unchanged. The motor body length and shaft extension are identical to the OEM unit, so no mechanical modification to the robot arm structure is required.

Q: What communication protocol does this motor use, and is it compatible with my existing KUKA system?
A: This motor uses the DRIVE-CLiQ digital encoder interface, which is the standard protocol for all SINAMICS S120-based KUKA robot drive systems. It is fully compatible with KRC2 (with SINAMICS S120 Combi) and KRC4 (with KPP/KSP servo packs) controllers without any protocol converter or gateway.

Q: Can this motor be used as a spare for multiple robot models?
A: The 1FK7101-5AY71-1SY3-Z is specified for high-torque axis applications (typically axis 1 or 2) on mid-to-large KUKA robot platforms. Confirm the axis torque and speed requirements against your robot’s axis data sheet before cross-applying to a different model. Contact our technical team with your robot model and axis number for confirmation.

Q: What should I check if the robot shows an F07900 (motor overtemperature) fault after installing the replacement?
A: Verify that the thermal sensor (KTY84 or PTC) connector is fully seated in the motor terminal box. An unseated thermal sensor connector will cause the drive to report a false overtemperature fault. Also confirm that the motor mounting surface is clean and that the motor is not thermally isolated by debris or insulating material.

Warranty Assurance

Every KUKA C26D00-100-782KCP2 / 1FK7101-5AY71-1SY3-Z S77 Servo Motor supplied by TOPNLMS is covered by a 12-month warranty from the date of shipment. Prior to dispatch, each unit undergoes a pre-shipment inspection that includes visual examination of the motor body, connector integrity check, encoder communication verification, and insulation resistance testing. Units that do not meet our outgoing quality standards are quarantined and not shipped.

In the event of a warranty claim, TOPNLMS provides a replacement unit or full refund within the warranty period, subject to inspection of the returned item. Our after-sales response target is within 24 hours of a warranty claim submission. We maintain buffer stock of common 1FK7 series motors to support rapid replacement dispatch, minimizing your production downtime during the warranty resolution process.

For urgent procurement requirements — including same-day quotation, express air freight, and customs documentation support for cross-border shipments — contact our industrial parts team directly. We serve customers across mainland China, Southeast Asia, Europe, and the Americas with competitive lead times and full traceability documentation.