The Siemens 3RT2926-3AB31 is a mechanical latch designed to hold a contactor closed without sustained coil power — useful for maintaining a circuit state during a control-voltage dropout or for applications where the contactor must stay engaged after a momentary signal. It fits SIRIUS S0 frame contactors: the 3RT202, 3RT232, and 3RT252 series. The latch clips onto the contactor front via the fastening method, adding 22 mm width to the assembly.
Coil voltage and tolerance window
Coil power draw is 4 W typical on DC and 4 VA typical on AC — low enough that a standard 24 VDC power supply or a small control transformer can drive it without derating.
Wiring and environmental limits
AWG equivalents are 2x 14 or 1x 12. The latch has no auxiliary contacts — it only provides the mechanical holding function. Mounting position is any orientation.