Siemens A5E39021143 Replacement for SINAMICS S120

Product Overview

Siemens A5E39021143 Replacement for SINAMICS S120: Seamless Transition & Legacy System Compatibility

Upgrading or replacing a failed Siemens A5E39021143 Power Unit within a SINAMICS S120 drive system demands more than a simple part swap. Industrial facilities running legacy SINAMICS S120 booksize or chassis configurations often face the challenge of sourcing a drop-in replacement that preserves existing wiring harnesses, DC bus connections, 24 V control supply architecture, and DRIVE-CLiQ topology — all without triggering a full-line shutdown. The A5E39021143 is a Smart Line Module or Power Module variant within the S120 family, designed to deliver regulated DC link voltage to connected Motor Modules such as the 6SL3120 series, while maintaining synchronization across the CU320-2 or CU310-2 Control Units already installed in the cabinet.

When the original A5E39021143 reaches end-of-life or suffers an unplanned failure, the migration path must account for physical form factor compatibility within the existing S120 booksize mounting rail, the 24 V PELV supply shared with adjacent components, and the DRIVE-CLiQ daisy-chain that links the Control Unit to downstream Motor Modules and encoder interfaces. Our replacement A5E39021143 units are sourced from authorized distribution channels, fully tested against Siemens factory acceptance criteria, and shipped with all original connectors and mounting hardware to ensure zero-modification installation.

Compatibility Comparison Table

Seamless Upgrade Solutions

A successful A5E39021143 replacement rarely involves the Power Unit alone. In most SINAMICS S120 retrofit projects, engineers simultaneously address adjacent components to eliminate latent failure risks and future downtime. The CU320-2 DP Control Unit, which orchestrates torque and speed commands across all axis groups, is frequently evaluated alongside the Power Unit replacement — particularly when the existing firmware version predates the A5E39021143’s hardware revision. Alongside the Control Unit, the DRIVE-CLiQ Hub Module DMC20 or DME20 may require inspection to confirm that the daisy-chain topology remains intact after the module swap.

On the motor side, the 6SL3120-series Double Motor Modules and Single Motor Modules connected downstream of the A5E39021143 should be verified for DC link voltage compatibility, especially in multi-axis servo applications where regenerative braking energy flows back through the DC bus. If the existing Braking Module (6SL3100 series) or Voltage Clamping Module is approaching its service interval, co-replacement during the same maintenance window significantly reduces total downtime.

For facilities migrating from older SIMODRIVE 611 or MASTERDRIVES MC platforms to the SINAMICS S120 architecture, the A5E39021143 Power Unit serves as the DC bus anchor for the new system. In these cross-generation migrations, the terminal adapter sets and shielding plates from the S120 accessory range ensure that legacy motor cables — often 4-core shielded with PE — can be terminated correctly without rewiring the motor junction box. The SITOP PSU100S 24 V power supply, already present in most S7-based control cabinets, provides the PELV supply required by the new module without any panel modification.

Where PROFINET IO is the plant communication backbone, the existing ET 200SP or ET 200MP distributed I/O stations connected to the S7-1500 PLC continue to operate without program changes, since the drive replacement does not alter the PROFINET device name or IP address assignment stored in the PLC project. Engineers using TIA Portal V16 or later can perform an online firmware update to the replacement CU320-2 PN directly from the engineering station, further reducing commissioning time on the shop floor.

Retrofit Guidance FAQ

Q: Can I reuse my existing wiring when replacing the A5E39021143?
Yes. The replacement unit uses identical connector positions for the DC bus busbars, DRIVE-CLiQ port, 24 V PELV input, and PE terminal. No rewiring is required provided the existing cables are within their rated service life.

Q: Will my PLC program need to be modified?
No. The SINAMICS S120 drive parameters are stored in the Control Unit (CU320-2 or CU310-2), not in the Power Unit. Replacing the A5E39021143 does not alter the parameter dataset. A backup via STARTER or Startdrive prior to replacement is recommended as standard practice.

Q: Is PROFIBUS DP or PROFINET IO communication affected?
No. Communication is managed by the Control Unit. The Power Unit replacement is transparent to the fieldbus layer. The S7-300, S7-400, or S7-1500 PLC will not detect any topology change on the network.

Q: Does the replacement unit fit the existing booksize mounting rail?
Yes. The A5E39021143 replacement shares the same booksize mechanical envelope. No cabinet modification, additional spacer, or new DIN rail section is required.

Q: How long does commissioning take after installation?
For a direct replacement with an intact parameter backup, recommissioning typically takes 30–90 minutes, covering visual inspection, DRIVE-CLiQ topology recognition, and a no-load test run. Full-load verification should follow standard site acceptance procedures.

Q: What if my original unit has a different firmware version?
The replacement unit ships with factory-loaded firmware. If your CU320-2 requires a specific firmware version for compatibility with your TIA Portal project, a firmware update can be performed via Startdrive before the unit is installed in the cabinet.

Warranty Assurance

Every A5E39021143 replacement unit supplied by TOPNLMS is covered by a 12-month warranty from the date of shipment. Prior to dispatch, each unit undergoes a multi-point outgoing inspection that includes DC bus insulation resistance testing, DRIVE-CLiQ port verification, 24 V auxiliary supply continuity check, and visual inspection of all connectors and busbars. Units that do not meet Siemens factory acceptance thresholds are quarantined and not shipped.

In the event of a warranty claim, TOPNLMS provides a replacement unit dispatch within 3 business days of fault confirmation, minimizing production interruption. Our after-sales team is reachable via email and phone to support fault diagnosis, parameter recovery, and on-site commissioning guidance. All warranty replacements are shipped with full documentation including test reports and packing declarations.

For urgent breakdown situations, expedited shipping to major industrial hubs in Asia, Europe, and the Americas is available. Stock availability is confirmed at the time of order, and a proforma invoice with lead time commitment is issued within 24 hours of inquiry.