The Siemens 6SL39546KX010AA0 is a metallized polypropylene (MKP) capacitor rated at 1.5 µF with a voltage rating of 2.5 kV. It's a DC-link or snubber capacitor used inside SINAMICS drive modules — the kind of part you swap when a drive throws a DC-link overvoltage or undervoltage fault and the electrolytics check out fine but the MKP has drifted or shorted.
1.5 µF at 2.5 kV is a specific value — not a generic 2 µF or 1 µF that might work in a pinch. The 2.5 kV DC rating handles the rail voltage in 400 VAC-class drives with headroom for regenerative peaks. If you're matching a failed cap on a SINAMICS G120 or S120 power stack, verify the original capacitance and voltage; swapping in a different value changes the ripple current handling and could shorten the electrolytic bank's life.
Deployment context
This capacitor mounts inside the drive enclosure — not a field-replaceable module. It is soldered or bolted to the DC bus bar. When ordering for a repair, pull the drive, discharge the bus, and replace this along with the electrolytics.