The Siemens 3RT1016-1DB42-ZW95 is a SIRIUS 3RT1 contactor rated AC-3 at 4 kW on a 400 V three-phase system — the standard motor-switching duty class for squirrel-cage induction motors. The 4 kW AC-3 rating means it handles the inrush and breaking of motor loads up to that power without welding or excessive contact erosion; it's the figure that governs fit for a pump, fan, or compressor on a 400 V line.
This variant ships in multiunit packing of 144 units per pack — a bulk configuration for OEM panel builders or MRO storerooms stocking a common frame size across multiple machines. The contactor mounts on a standard DIN rail inside a control cabinet, with screw terminals for power and control wiring. Spring-cage auxiliary contact blocks and surge suppressors from the same SIRIUS family snap onto the front without tools.