The Siemens 5TT5853-2 is a SENTRON Insta contactor — a panel-mount switching device designed to handle lighting and resistive loads, not motor starting. It carries 4 normally-closed (NC) contacts and zero normally-open (NO) contacts, so its job is to break a circuit on command, not make one. The contactor is rated for 440 V AC at 63 A and switches incandescent lamp loads up to 5000 W. The control coil is 24 V AC, not DC — a common trip point for anyone wiring it into a 24 VAC control transformer circuit.
The 4 NC contact arrangement means this contactor stays closed when de-energized — it's a fail-closed device. In a safety circuit or emergency-stop chain that requires the load to remain connected until the coil is deliberately powered, that matters. The 24 V AC coil is non-negotiable: wire it with 24 V DC and it won't pull in reliably. The manufacturer explicitly notes that spacers must be provided between units to ensure heat dissipation. Plan for at least one empty MW slot between this and the next heat-producing device.