Trip class and solid-state design — why it matters for motor protection
This is the standard for standard-duty motor starting — it allows the motor to accelerate under load without nuisance tripping while still protecting against locked-rotor conditions. As a solid-state overload relay, the 3RB3046-1XD0 has no bimetal strips to drift or age.
Current rating and voltage ceiling — sizing the relay to the motor
The thermal current rating is 115 A continuous, and this holds at both 480 V and 600 V rated values — no derating needed across common industrial voltage levels. The rated insulation voltage is 1,000 V, giving headroom for 690 V systems. Size S3 frame means this relay sits in the middle of the SIRIUS overload relay range, suited for motor full-load currents roughly between 30 A and 115 A depending on the setting range of the specific variant. The screw-type main terminals accept up to 2x 16 mm² stranded wire.
Auxiliary contact ratings — what the signaling circuit can handle
The integrated auxiliary switch provides a 'tripped' signal contact. The power dissipation per pole is 1.53 W at rated current. For a three-phase motor circuit, total heat load inside the enclosure is about 4.6 W — negligible for most panels, but worth noting if the relay is densely packed with other heat sources.
Mounts directly onto the contactor via the fastening method — no DIN rail or separate base required. The dimensions are 70 mm wide, 106 mm high, and 124 mm deep, matching the SIRIUS S3 contactor footprint. Any mounting position is permitted. The main circuit terminals use M6 screw-type connections with a Pozidriv PZ2 screwdriver tip. The screwdriver shaft diameter should be 5 to 6 mm for proper torque application.
Vibration resistance is tested to 1-6 Hz at 15 mm amplitude, then 6-500 Hz at 20 m/s² for 10 cycles. Shock resistance is 8g for 11 ms on the signaling contact in tripped position, and 15g for 11 ms on the main contact block per IEC 60068-2-27. Storage and transport temperature range is -40 to +80 °C. The substance prohibitance date of 03/01/2017 indicates RoHS compliance was confirmed from that date forward.