Two axes in one booksize slot
The 6SL5120-2UE21-8SD0 is a SINAMICS S220 Double Motor Module — two independent inverter axes sharing a single booksize chassis, fed from a 495-720 V DC link and each delivering 0-480 V 3AC at 18 A rated, good for 7.5 kW per axis. Cooling is internal-air only and the firmware floor is V5.2 SP3 HF10 or later, which means cabinet integration (not field mounting) and a commissioning step that pins the drive to a known control FW before the axes will accept motion commands.
Panel-side fit and what 18 A actually buys you
At 18 A per axis in S220 duty the module covers mid-range servo motors — typically the 7-9 kW frame — so a single slot drives two smaller axes (feed rolls, indexing tables, paired conveyors) instead of stacking two single-axis booksize modules. IP20 and the 365 x 565 x 60 mm booksize envelope place it inside a sealed cabinet; the heat load from internal-air cooling has to be budgeted against the cabinet heat exchanger, and the 60 mm face depth keeps the front-panel cable bend radius inside the standard wiring duct.
Compliance, export, and ordering taxonomy
RoHS compliance dates from 22-03-22 and REACH Art. 33 reporting applies — the part carries lead (CAS 7439-92-1) above the 0.1% w/w disclosure threshold, which is the standard high-density power-electronics exemption pattern and not a restriction on use. Export classification is AL:N / ECCN:3A999A, group code R220, product group X0HX — those internal codes map to Siemens' standard booksize double-module line and confirm a single-piece order unit with one drive per package.
Lifecycle and sourcing posture
Sourcing runs through independent distribution: quoted to order against the RFQ with availability, current pricing, and the firmware revision confirmed at quote time.