Plants do not stop running because Siemens ends production. When a part is discontinued you have two options: find a genuine original through the surplus and import market, or move to the successor range. We do both — and we will tell you honestly which one makes sense for your situation rather than pushing whichever is easier to sell.
Legacy ranges and their successors
SIMATIC S5 → SIMATIC S7-1500: Long obsolete. A full migration project — hardware, program and I/O all change.
SIMATIC S7-300 → SIMATIC S7-1500: S7-300 is phased out. Spares are still findable; migration is a project, not a swap.
SIMATIC S7-400 → SIMATIC S7-1500 / PCS 7: Late lifecycle. Plan shutdown spares early — supply is stock-driven.
MICROMASTER 4 (MM420 / MM430 / MM440) → SINAMICS G120 / G120C: Size to the same motor. Mounting, terminals and parameters all differ.
SIRIUS 3RT1 contactors → SIRIUS 3RT2: Usually the same footprint, but auxiliary blocks and terminal types changed.
3TF contactors → SIRIUS 3RT2: Older Siemens contactor generation; select by AC-3 current, not by old code.
SIRIUS 3RV1 motor protection → SIRIUS 3RV2: Accessories, link modules and busbars are not interchangeable between generations.
3RU11 overload relays → 3RU21: Match the current-setting band and the contactor frame it mounts on.
3SB3 pushbuttons → SIRIUS ACT 3SU1: Same 22 mm cut-out, but holder and contact blocks must be replaced as a set.
5SX miniature circuit breakers → SENTRON 5SY: Confirm curve and breaking capacity — do not assume the old rating carries over.
SIMOCODE 3UF5 → SIMOCODE pro 3UF7: Motor management system; parameterisation and communication both change.
Older SITOP PSU100S / PSU300S → SITOP PSU6200 / PSU8200: Check output rating, DIN footprint and terminal arrangement.
SIMATIC OP / TP legacy panels → SIMATIC HMI Comfort Panels: Panel cut-out and project conversion both need checking before ordering.
Frequently asked questions
Can you still find genuine obsolete Siemens parts?
Often yes. Our import network reaches surplus and end-of-line stock in several countries, and we regularly source parts Siemens itself no longer produces. What we will not do is promise something we cannot get — if a part is genuinely unfindable we will say so and quote the successor instead.
Is the successor a direct drop-in replacement?
Rarely, and we would rather tell you that up front. Successor ranges usually keep the function but change mounting, terminals, accessories or parameters. Send us the old part number and we will confirm exactly what changes before you commit.
Do you supply refurbished or used parts?
Where a genuine new part no longer exists, tested surplus is sometimes the only route to keep a line running, and we will say clearly what condition the item is in. We never present used stock as new.