VFD for Compressors: Selection Guide
How to select and size a VFD for screw, reciprocating and centrifugal compressors, covering overload rating, turndown limits and energy savings.
The Siemens SINAMICS G120 CU250S-2 control unit 6SL3246-0BA22-1BA0 adds sensorless and encoder-based vector control to a G120 power module, with Safe Torque Off, Safe Brake Control and Safe Stop 1 built in. It provides 6 configurable digital inputs, 3 digital outputs, 2 analog inputs, 2 analog outputs, and an integrated RS485 interface for USS/Modbus RTU, all in an IP20 / UL open type enclosure.
Pick the CU250S-2 over the base CU240 line when the application needs closed-loop vector control with an encoder (D-CLiQ, HTL/TTL, SSI, or resolver via terminal) or the Basic Positioner (EPOS) function, which requires the license extension noted in the Siemens description. The 3 fail-safe digital inputs and Safe Torque Off / Safe Brake Control / Safe Stop 1 cover most machinery safety category needs without an external safety relay; the Extended Safety license adds further safe functions if the machine also needs SLS or SS2. This is a control unit only and must be matched to a G120 power module of the appropriate power rating to form a complete drive.
Suited to G120 modular drive builds that need encoder feedback, positioning, or integrated safety at the drive level: conveyor sections, hoists, and machine axes where Safe Torque Off replaces a separate contactor-based safety circuit.
| Operating voltage via: The Power Module | DC 24 V |
|---|---|
| Operating voltage via: External power supply | DC 20 ... 29 V |
| Operating voltage via: Max. power consumption | 2.00 A |
| Operating voltage via: Power loss | 12.00 W |
| Communication | RS485 |
|---|
| Standard digital inputs: Number | 15 |
|---|---|
| Standard digital inputs: Switching level: 0→1 | 11 V |
| Standard digital inputs: Switching level: 1→0 | 5V |
| as relay changer: Number | 2 |
| Analog / digital inputs: Number | 2 (Differential input) |
| Analog outputs: Number | 2 (Non-isolated output) |
| Part number | 6SL3246-0BA22-1BA0 |
|---|---|
| Brand | Siemens |
| Condition | New, factory sealed |
| Source | Siemens and its authorised distributors |
| Warranty | Manufacturer warranty |
| EAN | 4042948664094 |
| V/f with flux current control (FCC) | 1 |
|---|---|
| V/f ECO linear / square-law | 1 |
| Sensorless vector control | 1 |
| Vector control, with sensor | 1 |
| Encoderless torque control | 1 |
| Torque control, with encoder | 1 |
| Ambient temperature: Operation | -10 ... 50 °C (14 ... 122 °F) |
|---|---|
| Ambient temperature: Storage | -40 ... 70 °C (-40 ... 158 °F) |
| Relative humidity: Max. operation | 95 % 0.05 ... 1.50 mm² (AWG 28 ... AWG 16) |
| Degree of protection | IP20 / UL open type |
|---|---|
| Dimensions: Width | 73.0 mm (2.87 in) |
| Dimensions: Height | 199.0 mm (7.83 in) |
| Dimensions: Depth | 67.0 mm (2.64 in) |
| Compliance with standards | CE, UL, cUL, RCM, SEMI F47 |
|---|---|
| CE marking | Low-voltage directive 2014/35/EC |
| Page 1 of 1 | Generated Sun Nov 1 04:07:47 CET 2026 |
| Net weight | 0.61 kg |
|---|---|
| Shipping weight | 1.11 kg |
| Ships from | Türkiye |
| Dispatch | 13 Nov |
| Stock | In stock |
Source: manufacturer data · Last verified: 01 Nov 2026
No documents are on file for this part yet.
Ask us for the datasheetThe tariff (HS) code on file for 6SL3246-0BA22-1BA0 is 85371091.
The EAN (GTIN) of 6SL3246-0BA22-1BA0 is 4042948664094.
6SL3246-0BA22-1BA0 ships from Türkiye. Shipping calculated at checkout · import duties and taxes paid on arrival. Stock items are dispatched within 1–2 business days.
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