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Siemens SIMOREG DC Master 6RA70
SIMOREG DC Master units are Siemens microprocessor-controlled thyristor converters for DC motors, with part numbers starting with 6RA70. They are the generation that followed SIMOREG K and preceded today's SINAMICS DCM (6RA80).
They are widely used in rolling mills, hoisting, paper mills, extrusion, winders and test benches. The E-Repair catalogue covers 111 6RA70 converters and 35 6RY17 spare boards, all of which can be assessed for repair.
⚙️ Versions
- Single quadrant (B6C bridge): for drives that run in one direction only without regenerative braking. In the catalogue: about 40 part numbers.
- Four quadrant (antiparallel (B6)A(B6)C bridge): reversal of the direction of rotation and braking with energy recovery to the mains.
The E-Repair catalogue includes converters for mains voltages of 400 V, 460 V, 575 V, 690 V and 830 V, from 15 A sizes up to more than 800 A. The full part number indicates voltage, current and bridge type.
👉 6RA7025-6DS22-0 – single-quadrant SIMOREG DC Master
👉 Search the catalogue: 6RA70
The most numerous roots are for example 6RA7085 and 6RA7095, DC Master converters with microprocessor, for example for single-quadrant drives.
🧩 6RY17 spare boards
Many DC Master faults can be solved by working on a single board. The E-Repair catalogue includes, among others:
- control electronics with terminal blocks (references C98043-A7001)
- power interfaces, also for versions up to 690 V (references C98043-A7002, A7003 and others)
- field supply for different excitation currents (references C98043-A7004, A7014)
- TSE modules and capacitor modules (references C98043-A7007)
- firing transformers and voltage measurement boards
- power sections for the small sizes
👉 6RY1703-0AA00 – control electronics with terminal blocks
👉 Search the catalogue: 6RY17
When the control electronics are replaced, the parameters must be saved and reloaded, otherwise the converter will not resume working as before.
⚠️ Typical faults
- thyristors damaged by overcurrents, short circuits or motor faults
- faulty field supply, with loss of excitation
- faults in the control electronics or power interfaces
- fuses and protections tripped by repeated overloads
- parameters lost after faults or replacements, when no backup is available
🔄 DC Master or SINAMICS DCM?
SINAMICS DCM (6RA80) is the successor to the DC Master. The changeover requires a technical assessment, because the electronics, software and some connections change. For many plants the most efficient choice is to keep the DC Master running through repair and refurbishment, and to plan the upgrade around production schedules.
🧩 Other spare boards (6RY1803)
The catalogue also includes 6RY1803 boards, such as Power Interface with terminals and field supply modules (4 part numbers).
🛠️ E-Repair services for SIMOREG DC Master
As Approved Partner Siemens – Industry Services, E-Repair supports the production continuity of DC drive plants:
🔧 Component-level repair of converters and boards in E-Repair's certified in-house laboratory, where technically feasible.
♻️ Refurbishment with inspection and replacement of components subject to ageing, and functional testing according to the agreed scope of work.
🚚 Advance replacement with a refurbished or new converter or board, if available in stock and after a compatibility check.
🛠️ On-site and remote technical assistance for diagnosis and support with recommissioning.
💾 Support in saving and restoring parameters.
✅ Standard 12-month warranty on the services for which it applies, extendable up to 24 months under the applicable conditions.
❓ Frequently asked questions
✔️ Can just the faulty board be repaired?
Often yes. The E-Repair diagnosis shows whether the fault is limited to a 6RY17 board or also involves the power section.
✔️ Can a single-quadrant converter replace a four-quadrant one?
No, if the application requires reversal or regenerative braking. Always check the full part number of the installed unit.
✔️ What is needed for the diagnosis?
The full part number, the last fault message shown on the panel and, if possible, a parameter backup.
📚 Further reading
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.
