Siemens 3RT7027-1AM00 SIRIUS Contactor — S0 Frame, AC-3 Duty
The Siemens 3RT7027-1AM00 is a 3-pole SIRIUS contactor in the S0 frame size, rated for AC-3 switching up to 690 V. It carries a 45 mm width and 91 mm depth, fitting standard 35 mm DIN rail per EN 50022 with screw and snap-on mounting. The control supply is AC; the magnet coil draws 0.24 W holding power at DC. Main contacts are 3 NO; no NC main contacts are fitted. Auxiliary contacts are rated for PLC-level signals (17 V, 5 mA), making them suitable for direct digital input interfaces without interposing relays.
AC-3 and DC-13 Ratings — What They Mean for Motor and Inductive Loads
The AC-3 rating at 690 V defines the maximum operating voltage for motor switching — this contactor handles motor loads up to that line voltage in standard starting/running duty. The DC-13 rating at 220 V (0.3 A) covers inductive DC loads such as solenoid valves or DC brake coils. For AC-3 duty, the maximum operating rate is 800 operations per hour; for AC-4 (plugging/reversing), it drops to 250 operations per hour. These rates govern thermal rise in the contactor — exceeding them shortens electrical life.
Mounting and Integration — DIN Rail, Side-by-Side, and Orientation
Mounts on 35 mm DIN rail per EN 50022 via screw and snap-on fastening. Side-by-side mounting is permitted, so multiple contactors can pack tightly on the rail without derating. The mounting position allows +/-180° rotation on a vertical surface and +/-22.5° tilt forward/backward — useful for angled panel layouts. Pollution degree 3 means it's rated for industrial environments with conductive pollution. IP20 on the front and terminals provides finger-safe touch protection; no washdown rating, so keep it inside the enclosure.
Fuse Coordination and Short-Circuit Protection
For type 2 coordination (no damage to the contactor after a fault), the required upstream fuse is a gL/gG NH 3NA rated 50 A. For type 1 coordination (contactor may need replacement after fault), the fuse rating is 125 A. These values assume the main circuit is protected by the listed fuse types — essential for selectivity studies in panel design. The contactor itself is rated for a rated insulation voltage of 690 V and surge voltage resistance of 6 kV.