What it is and what it does
The Siemens 3RT1015-1AK61-ZX95 is a SIRIUS power contactor in the compact S00 frame size, designed for switching motor loads and resistive loads in control panels. It carries a 110 V 50 Hz / 120 V 60 Hz coil and provides a rated operating current of 10 A in AC-12 duty, which means it handles resistive and transformer loads up to that current. For motor switching, it is rated 3 kW at 400 V in AC-2 duty (slip-ring motors) and 6.5 A at 400 V in AC-4 duty (plugging/inching). The contactor mounts via screw or snap-on onto a 35 mm DIN rail per EN 50022, and its 45 mm width allows side-by-side mounting with zero clearance.
Key ratings and what they mean for fit
The coil tolerance spans 0.85 to 1.1 times rated voltage at 50 Hz and 0.8 to 1.1 at 60 Hz — so at 110 V 50 Hz, the coil picks up reliably down to about 93.5 V and holds in up to 121 V. That's a wider dropout margin than some older contactors, useful if your control transformer sags under inrush. The main circuit uses screw-type terminals accepting 2x (0.5 to 1.5 mm²) solid or 2x (0.75 to 2.5 mm²) stranded, with a maximum of 2x 4 mm². For AWG, that's 2x (20 to 16) solid or 2x (18 to 14) stranded. The auxiliary contact block provides 1 normally-open instantaneous contact rated 10 A at 24 V, 6 A at 230 V, and 3 A at 400 V — enough for a PLC input or a holding circuit interlock.
Integration and environment
The contactor fits a standard 35 mm DIN rail per EN 50022, and side-by-side mounting is permitted with a 6 mm clearance at the side for heat dissipation. The front of the device and the terminals are rated IP20 — finger-safe but not protected against moisture, so it belongs inside a panel rated IP54 or better. Operating temperature range is -25 to +60 °C, and the maximum installation altitude is 2,000 m without derating. Pollution degree 3 means it tolerates conductive pollution in industrial environments, which is typical for a contactor in a motor control center.
Coordination and protection
For short-circuit protection, the manufacturer specifies two coordination types. With Type 1 coordination (no damage to the contactor but may not be suitable for further service without inspection), use a gL/gG fuse rated up to 35 A. With Type 2 coordination (contactor remains suitable for further service after a fault), use a gL/gG fuse rated up to 20 A. These fuse ratings assume the contactor is paired with an appropriate overload relay — the contactor itself does not have integral overload protection.