Siemens SINAMICS S120 Cabinet Modules: multi-motor drives in cabinets

SINAMICS S120 Cabinet Modules are the cabinet version of the S120 system, designed for high-power multi-motor plants: several motors connected to a common DC bus, fed by one or more line modules. They are found on continuous paper and film machines, rolling mills, process lines, cranes and test benches.

The E-Repair catalogue covers 128 S120 Cabinet Modules part numbers.

⚙️ How a cabinet S120 system is built

• Line Module: feeds the common DC bus from the mains. It comes in three variants: Basic Line Module, without energy recovery; Smart Line Module, with energy recovery to the mains; Active Line Module, with controlled recovery and almost sinusoidal line current.
• Motor Module: one cabinet for each motor or group of motors, fed by the common bus.
• Control unit of the S120 platform and auxiliary modules.

🔍 Roots in the E-Repair catalogue

👉 Search the catalogue: 6SL3720 · 6SL3730

⚠️ Typical faults

• power modules damaged by overloads or motor faults
• Line Module faults, which stop all motors connected to the bus
• worn fans, capacitors and internal power supplies
• faulty control boards and DRIVE-CLiQ interfaces

Many cabinet interventions are solved by replacing individual internal components, such as power blocks, interface boards or fans: see the guide to SINAMICS spare parts for chassis units.

🛠️ E-Repair services for SINAMICS S120 Cabinet Modules

As Approved Partner Siemens – Industry Services, E-Repair supports production continuity:

🔧 Component-level repair in E-Repair's certified in-house laboratory, with diagnosis and repair where technically feasible.

♻️ Refurbishment with replacement of components subject to ageing and functional testing according to the agreed scope of work.

🚚 Advance replacement with a refurbished or new product, if available in stock and after a compatibility check.

💾 Support in saving and restoring parameters and firmware.

🛠️ On-site and remote technical assistance for diagnosis and recommissioning.

✅ Standard 12-month warranty on the services for which it applies, extendable up to 24 months under the applicable conditions.

❓ Frequently asked questions

✔️ If the Line Module fails, does the whole plant stop?

Yes, in configurations with a single Line Module all Motor Modules connected to the bus stop. A ready spare or an advance replacement service drastically reduces downtime.

✔️ What is the difference between Basic, Smart and Active Line Modules?

The Basic feeds the bus without returning energy; the Smart can return energy to the mains; the Active returns it in a controlled way, with less mains interference.

✔️ What is needed for the diagnosis?

The full part number of the cabinet or module, the fault messages and, if possible, a backup of the project and parameters.

📚 Further reading

👉 SINAMICS range · 👉 S120 line modules · 👉 S120 motor modules · 👉 S120 control modules

ℹ️ The information provided is general and indicative. Before purchase, installation or commissioning, check the data against the official Siemens documentation or contact E-Repair.