The Siemens 3RK1301-0BB00-0AA2 is a SIMATIC-branded direct motor starter — a compact, integrated unit that combines a contactor, overload relay, and short-circuit protection into one device for controlling a single three-phase motor in a direct-on-line (DOL) start configuration. Communication is built in: the starter supports both PROFINET and PROFIBUS DP protocols, so it drops directly into a Siemens automation network without an extra gateway module.
Mounting, wiring, and panel fit
The starter measures 45 mm wide by 265 mm tall by 120 mm deep — a 45 mm footprint on the DIN rail, which is a standard width for a motor starter of this class. The 120 mm depth means it will sit proud of the backplane, so check enclosure depth clearance before laying out the panel. It fastens by plugging onto a terminal module — the power and control wiring lands on a base unit, and the starter module clips onto it. This means you can pre-wire the panel and snap the starter in later, or swap a failed starter without disturbing the wiring. The main energy infeed uses screw-type terminals, so expect to torque down ring or fork lugs on the power connections — no spring-cage on the main feed. Mounting position is flexible: vertical or horizontal orientation is permitted, which helps when laying out dense panels where rail space is tight.
Control voltage and environmental limits
The control circuit is 24 V DC nominal, with a permissible range of 20.4 to 28.8 V DC — standard for industrial 24 V supplies. The maximum permissible voltage is 28.8 V, so do not exceed that even on a float-charged battery backup. The unit is rated for vibration resistance of 2g and shock resistance of 5g / 11 ms — robust enough for machine-mounted applications near rotating equipment. Pollution degree rating is 3 at 400 V and 2 at 500 V per IEC 60664 / IEC 61131 — pollution degree 3 means the environment is industrial with conductive or dry non-conductive pollution, which is the standard assumption for most control panels not in a clean room.
No successor has been announced, and no cross-reference to a different series is needed — this is the part to specify.