Start with the motion: continuous speed means a VFD (V20, G120C, G120, G120X, G220); positioning means a servo (V90, S200, S210, S120). Then filter by power and supply, application (pump vs heavy start), communication, safety and mounting. Size by motor current and overload class, not kW, and confirm in the TIA Selection Tool.
- Continuous speed → VFD. Positioning → servo.
- Pumps/fans: G120X or V20. Machines: G120C or G220.
- Size by current: LO for pumps, HO for heavy starts.
- Need STO or PROFINET? Not V20.
The SINAMICS Portfolio at a Glance
Six Questions That Decide the Drive
| # | Question | Why it matters |
|---|---|---|
| 1 | Continuous speed or positioning? | VFD family vs servo family |
| 2 | Motor power, current and supply? | Power range, 1-ph vs 3-ph, frame size |
| 3 | What load? Pump/fan vs heavy start | Control mode and overload class (LO/HO) |
| 4 | How is it controlled? | Terminals, Modbus/USS, PROFINET |
| 5 | Which safety function? | None, STO on terminals, PROFIsafe/extended |
| 6 | Where is it mounted? | Cabinet IP20 vs on-machine IP65 |
Not sure which drive fits?
Send us your motor and application, and our trainers will suggest a SINAMICS family. Or learn selection and commissioning hands-on.
Interactive SINAMICS Drive Selector with MLFB Number
Answer the questions and the selector proposes the family and, for G120C and V20, the exact MLFB (article number), decoded and sized by current at your overload duty.
Article numbers are generated from the published G120C and V20 numbering for 400 V units, and the drive is sized by current at the chosen overload. This is a training aid: confirm the final order number, options and accessories in the Siemens TIA Selection Tool or SiePortal before ordering.
Sizing: Current and Overload, Not kW
| Duty | Typical loads | Select |
|---|---|---|
| Low overload (LO) | Pumps, fans, compressors | Drive LO current ≥ motor rated current |
| High overload (HO) | Conveyors, crushers, mixers, hoists | Drive HO current ≥ motor current (often one size up) |
| Derating | Altitude, ambient, pulse frequency, long cables, multi-motor | Apply manufacturer derating, then re-check |
Family Comparison
| Family | Approx. power | Best for | Communication | Safety | Engineering |
|---|---|---|---|---|---|
| V20 | 0.12–30 kW | Basic pumps, fans, conveyors | Terminals, USS/Modbus RTU | — | BOP / Smart Access |
| G120C | 0.55–132 kW | Compact machine drive | PROFINET/EtherNet/IP, PROFIBUS or USS/Modbus variants | STO | Startdrive / STARTER |
| G120X | 0.75–630 kW | Pumps, fans, compressors | PROFINET, Modbus, BACnet (variants) | STO | Startdrive |
| G120 | 0.55–250 kW | Modular CU + PM, encoder, safety | PROFINET, PROFIBUS, others | STO to extended (CU-dependent) | Startdrive / STARTER |
| G220 | 0.55–160 kW | New-gen high performance | PROFINET | STO/SS1 terminals | Startdrive |
| G115D / G120D | ≈0.37–7.5 kW | Distributed IP65 conveyors | PROFINET / AS-i (variants) | STO (variants) | Startdrive |
| V90 | ≈0.05–7 kW | Basic servo, pulse train / PN | PTI, PROFINET | STO | V-ASSISTANT / Startdrive |
| S200 | 0.1–7 kW | Standard servo | PROFINET or PTI | STO | Startdrive / web server |
| S210 | ≤ 7 kW | Dynamic single-axis servo | PROFINET | STO, extended via PROFIsafe | Startdrive |
| S120 | up to MW range | Multi-axis, high-end systems | PROFINET, PROFIBUS, DRIVE-CLiQ | Extended | Startdrive / STARTER |
Ranges and options are approximate and change between releases; verify in the current Siemens catalogue or TIA Selection Tool. Compare servo and VFD in Servo Drive vs VFD.
Plant Architecture: Standardise the Network
Hands-On Lab: Select and Size a Drive
Hands-on- '+LABPRE+'
Collect the motor data
Read the nameplate: voltage, current, power, speed, Δ/Y and cooling.
Describe the duty
Note start torque, cycle, overload, ambient and cable length.
Run the selector
Use the selector above to get a family and alternatives.
Confirm in the TIA Selection Tool
Enter the motor and duty, and pick communication, safety and options.
Check the result
Compare drive current at the chosen overload with the motor current, after derating.
'+CHECK+'
Frequently asked questions
How is a SINAMICS G120C MLFB (article number) built?
For the 400 V G120C it reads 6SL3210-1KE + power code + filter + fieldbus + version: for example 6SL3210-1KE21-7AF1 is 7.5 kW (LO), A = integrated class A filter, F = PROFINET/EtherNet/IP, version 1. U means no filter, P is PROFIBUS DP and B is USS/Modbus RTU. Always confirm the final number in the TIA Selection Tool or SiePortal.
How do I choose between SINAMICS V20 and G120C?
Choose V20 for simple, cost-sensitive pumps, fans and conveyors on terminals or Modbus/USS up to about 30 kW. Choose G120C when you need PROFINET, STO on terminals, vector control or more power (up to 132 kW). V20 has no STO.
When should I use G120X instead of G120C?
G120X is the pump, fan and compressor specialist up to 630 kW, with infrastructure functions such as multi-pump control. For general machines, conveyors and mixed loads, G120C or G120 is the usual choice.
What is SINAMICS G220?
G220 is Siemens’ newer-generation general-purpose converter, positioned above G120 for higher performance and digitalisation. It is engineered in Startdrive (TIA Portal) and suits demanding machines such as extruders and high-torque drives.
Should I select a drive by kW or by current?
By current. Match or exceed the motor’s rated current at the right overload class: low overload (LO) for pumps and fans, high overload (HO) for heavy starting loads such as conveyors and crushers. Then apply derating for ambient, altitude, pulse frequency and cable length.
When do I need a servo drive instead of a VFD?
When the task is positioning, fast indexing or tightly synchronised motion with high dynamics. Use S200 or S210 for single axes up to about 7 kW, S120 for multi-axis or higher power. A VFD is right for continuous speed control.
How do I get the exact order number?
Use the Siemens TIA Selection Tool or the SINAMICS Selector app with your motor data, duty, supply, communication, safety and options. A selection guide narrows the family; the tool confirms the exact rating and accessories.