Active production — what it means for your BOM line
The 3RW4028-1BB15: No stock-holding claim is made here — the supply posture is quoted to order.
Rated current and thermal derating — the real operating envelope
The continuous rated current is 38 A at 40 °C ambient. The derating temperature threshold is 40 °C, so any panel ambient above that must be factored into the motor full-load current match. The minimum load requirement is 20% of the rated current — below that the soft starter may not trigger the thyristors reliably. This matters when the connected motor is oversized for the actual load. Insulation voltage is rated at 600 V, with a pollution degree of 3 per IEC 60947-4-2. The operating frequency range is 50 to 60 Hz, covering standard industrial mains worldwide.
Mounting, clearances, and panel integration
Size S0 footprint: 45 mm wide, 125 mm high, 155 mm deep. Fastening is by screw and snap-on mounting onto a DIN rail — the snap-on feature speeds panel assembly without tools. Clearance requirements: 60 mm upwards, 40 mm downwards, 15 mm at the sides. These are the minimum free-air gaps for natural convection cooling; crowding the enclosure beyond these limits forces derating. Mounting position restrictions depend on whether an additional fan is fitted. With the fan, the unit can be rotated +/-90° on a vertical surface and tilted +/-22.5° front-to-back. Without the fan, rotation is limited to +/-10° and tilt to +/-10°.
Control supply and wiring
The control supply voltage accepts 110 to 230 V DC — a wide-range input that simplifies panel wiring across different control voltages without a separate transformer tap. Auxiliary and control circuit terminals are also screw-type, sized for 20 to 14 AWG. The front clamping point accepts one 8 AWG or two conductors from 16 to 10 AWG. Maximum motor wire length is 300 m — beyond that, voltage drop and reflected wave effects on the thyristor stack may cause nuisance tripping or premature failure.
Integrated bypass and protection features
An integrated bypass contact system is built in — once the motor reaches full speed, the bypass contacts close to short-circuit the thyristors, eliminating heat dissipation in the power semiconductors during steady-state running. This means the soft starter runs cool and the enclosure heat load is lower than a non-bypassed design. Motor overload protection and intrinsic device protection are both included. The adjustable current limitation allows setting the start current between 20% and 100% of the rated current, matching the application's torque requirements. External reset capability is provided — the fault signal is indicated by a red display. There is no motor brake output on this variant.
Environmental ratings and storage conditions
Storage temperature range is -40 to +80 °C. During storage, the unit meets IEC 60721 classifications 1K6 (occasional condensation), 1C2 (no salt mist), 1S2 (sand must not enter the device), and 1M4 (mechanical vibration). The reference code per EN 61346-2 is Q, designating a power switching device in the functional classification system.