The Siemens 6SL3210-1PE21-8UL0 is a SINAMICS G120 Power Module PM240-2 built for dependable variable-speed control of three-phase AC motors in industrial automation. It sits in the “power stage” role of the modular SINAMICS G120 concept: you pair the power module with a compatible control unit and (optionally) an operator interface to create a complete drive system. This modular approach is popular with panel builders and OEMs because it lets you standardize cabinet layouts while still adapting control features and fieldbus options to different machines.
What makes 6SL3210-1PE21-8UL0 especially practical is that it lands in the sweet spot of many factories: 3-phase 380–480 V AC supply environments, with a size and power range that fits common conveyors, pumps, fans, mixers, and general-purpose motion tasks. It is specified as “without filter” and with a built-in braking chopper, which is an important combination for real projects: you can design EMC (electromagnetic compatibility) strategy with external filtering as needed, while still having a straightforward path to controlled deceleration through a braking resistor when the application generates energy during stopping.
Another key idea with PM240-2 is two duty profiles: High Overload (HO) and Low Overload (LO). This is not marketing fluff; it directly affects how much torque your machine can produce during acceleration and how much thermal headroom the drive needs. For HO, the module is rated 5.5 kW (IEC 400 V) and supports 200% overload for 3 seconds plus 150% overload for 57 seconds (cycle time 300 seconds). For LO, it is rated 7.5 kW (IEC 400 V) and supports 150% overload for 3 seconds plus 110% overload for 57 seconds (cycle time 300 seconds). In simple terms: HO is the “more punchy acceleration” setting, LO is the “more continuous power” setting, assuming your cooling and ambient conditions match the limits.
Mechanically, this unit is designed for installation inside a cabinet and is specified as IP20 / UL open type. It uses plug-in screw terminals, and Siemens provides practical constraints for cable sizing and motor cable length—details that matter when you want an installation that survives vibration, maintenance, and time.
Technical Specifications Table (Key Data)
| Parameter | Value / Description |
|---|---|
| Product / Family | SINAMICS G120 Power Module PM240-2 |
| Order Number | 6SL3210-1PE21-8UL0 |
| Supply (Input) | 3 AC 380…480 V ±10%, 47…63 Hz |
| Filter / Braking | Without filter, built-in braking chopper |
| Rated Power (IEC 400 V) | 7.5 kW (LO), 5.5 kW (HO) |
| Rated Input Current | 22.2 A (LO), 19.8 A (HO) |
| Rated Output Current | 18.0 A (LO), 13.2 A (HO) |
| Max Output Current | 27.0 A |
| Output Frequency Range | 0…200 Hz (V/f control); up to 0…550 Hz (vector control) |
| Overload Capability | LO: 150% 3 s, 110% 57 s; HO: 200% 3 s, 150% 57 s (cycle 300 s) |
| Pulse Frequency | 4 kHz |
| Cooling | Internal air cooling; cooling air requirement 0.009 m³/s (≈9.2 l/s) |
| Ambient Limits | LO operation -5…40 °C; HO operation -5…50 °C; RH 95% (no condensation) |
| Installation Altitude | 1000 m (reference point; derating may apply above this) |
| Protection / Type | IP20 / UL open type |
| Dimensions (H×W×D) | approx. 292 × 100 × 165 mm |
| Net Weight | 3.00 kg |
| Connections | Plug-in screw terminals |
| Conductor Cross-Section | 1.5…6.0 mm² (AWG 16…10) line and motor side |
| Motor Cable Length | 100 m unshielded, 50 m shielded |
| Standards (per datasheet) | UL, cUL, CE, RCM, SEMI F47 |
Why “Built-In Braking Chopper” Matters in Daily Use
Many machines don’t just consume energy; they sometimes return it. When you decelerate a rotating load (a conveyor with inertia, a fan ramping down quickly, a mixer stopping on command), the motor can act like a generator. The built-in braking chopper gives the drive a built-in mechanism to handle that regenerated energy by routing it to a braking resistor (selected separately according to application needs). This can improve stopping consistency and reduce nuisance trips in applications that brake frequently.
Selection Notes That Prevent Pain Later
| Design Topic | What People Get Wrong | What to Do Instead |
|---|---|---|
| HO vs LO rating | Choosing by kW only, ignoring duty cycle | Use HO if you need stronger acceleration or short bursts; use LO when continuous load dominates |
| Cabinet thermal design | “It fits” is not the same as “it cools” | Respect airflow requirement and ambient limits; plan ducting/spacing so the module can breathe |
| EMC strategy | Assuming “no filter” equals “no compliance” | Treat “without filter” as a design choice: add external filtering and good cable practice as needed |
| Braking | Ignoring decel energy until commissioning | If decel is aggressive or frequent, plan braking resistor sizing early since the chopper is available |
| Cable length | Running long motor cables without considering limits | Follow the specified motor cable length guidance and shielding approach |
Typical Application Fit (Practical, Not Fantasy)
This module’s 7.5 kW LO / 5.5 kW HO range and 380–480 V supply class make it a strong match for a large set of industrial “workhorse” machines. The most common wins are in systems that need stable speed control, controlled acceleration, and predictable stopping behavior.
| Application Type | Why It Fits | Which Duty Profile Often Fits |
|---|---|---|
| Pumps and fans | Variable speed saves energy and reduces mechanical stress | Often LO (continuous load) |
| Conveyors and material handling | Start/stop behavior and load variation benefit from inverter control | Often HO if starts are heavy |
| Mixers and agitators | Smooth ramping reduces mechanical shock | Depends on inertia and start torque needs |
| General automation machines | Modular G120 concept supports standardized cabinets | Choose HO/LO based on cycle profile |
Siemens 6SL3210-1PE21-8UL0 is a compact, cabinet-mounted SINAMICS G120 PM240-2 power module for 3-phase 380–480 V industrial systems, offering a flexible HO/LO duty concept, no integrated filter, and a built-in braking chopper for controlled deceleration design. With defined overload behavior, specified cabling limits, and straightforward mechanical integration (IP20 / UL open type), it is engineered for real automation cabinets—where uptime, maintainability, and predictable performance matter more than fancy words.
