6SL3210-1KE21-3UB1 Variable Frequency Drive Sinamics G120 5.5kW 3-ф/380

6SL3210-1KE21-3UB1 is a PM240 Power Module from the Siemens SINAMICS G120 series rated 5.5 kW, three-phase 380 V supply, rated current 12.5 A. This is the power stage: to drive a motor it needs a Control Unit (CU) and usually an operator panel. It has a braking chopper for an external braking resistor to dissipate braking energy.

Typical applications:

• Pumping stations, second-lift pumps
• Supply/extract ventilation of malls and offices
• Conveyors, mixers, mid-power compressors

Note: Without a built-in EMC filter — for cabinets where a filter already sits on the supply or emission limits are met another way. IP rating, maximum frequency and the interface set are defined by the chosen Control Unit. For a simple single-pump job a cheaper alternative is the all-in-one Veichi AC310.

Siemens SINAMICS G120 — a modular variable frequency drive: understand what you are buying first

The key thing to grasp about the G120 before ordering: it is not a ready-to-run inverter out of the box. It is a modular system. The items in this section are Power Modules — the power stage. To make a module turn a motor you also need a Control Unit (CU230/CU240/CU250) and usually an operator panel. Engineers who have worked with the G120 know this; first-timers often order a "7.5 kW inverter" and wonder why it won't power up. That is why we always confirm the configuration.

Every module in this list is three-phase 380 V, power range 0.7–75 kW. The application area is the Siemens classic in machine building and infrastructure: pumps, fans, compressors, conveyors, mixers, hoists.

PM240 or PM250 — the difference

There are two Power Module families here, and you choose between them by how they brake:

• PM240 (article numbers 6SL3210-1KE… and 6SL3224-0BE…) — standard module with a braking chopper. It dumps braking energy into an external braking resistor as heat. Fits most jobs — pumps, fans, conveyors.
• PM250 (article numbers 6SL3210-1NE… and 6SL3225-0BE…) — a regenerative module. It feeds braking energy back into the line, so no external resistor is needed. Choose it where the motor brakes often and hard: hoists, centrifuges, downhill conveyors, high inertia loads.

With or without filter (EMC)

The second axis of choice is the built-in electromagnetic compatibility filter:

The 0BE versions with a built-in Class A filter are handy when you have no room or no wish to add a separate line filter in the cabinet. The unfiltered KE/NE versions are chosen when a filter already sits on the supply or emission limits are met another way — and they cost less.

When the G120 fits — and when something simpler is better

The G120 is the logical pick if the plant is already standardised on Siemens and TIA Portal, needs PROFINET/PROFIsafe integration, or specifically needs line regeneration (PM250). It is a premium modular platform with a long lifecycle and available service.

• For a simple single-pump station or an extract fan, the G120's modularity is extra cost and extra order lines. Look at the all-in-one Veichi AC310 — its control unit is already inside.
• There are no single-phase 220 V modules in this list — everything is three-phase 380 V.
• IP rating, maximum frequency and the interface set depend on the chosen Control Unit, so we do not state them here.

Our experience

Customers mostly take the G120 for existing Siemens automation or for regeneration jobs. The usual confusion is around the "power module + CU + panel" set. So before paying, tell us the application and motor type — we will suggest the right combination, and where it makes sense, a cheaper alternative.