63 A motor starting — what the rating means for the install
The 3RW3037-2BB04: For a motor with a 50 A FLA at 40 °C ambient, this starter holds headroom through the derating curve without upsizing the frame. The integrated bypass contact system eliminates the external bypass contactor and its wiring — the thyristors fire only during the start ramp, then the bypass relay closes, shunting current away from the semiconductors. This cuts heat dissipation in the panel during run and extends the life of the power stack.
Panel fit — S2 frame, mounting, and clearances
The S2 frame measures 55 mm wide, 160 mm high, and 170 mm deep — a compact footprint that fits a 6-module-wide DIN rail slot. Screw and snap-on mounting lets you either clip it onto the rail or bolt it directly to the backplate; the snap-on feature speeds replacement in a panel where the rail is already populated. Clearance requirements: 60 mm above, 40 mm below, and 30 mm at the side. These are the minimum air gaps for airflow and wiring access — stack them tighter and the derating curve shifts. The mounting position allows ±10° rotation and ±10° tilt from vertical, useful when the panel has a sloped gland plate. Pollution degree 3 per IEC 60947-4-2 means the creepage distances are designed for conductive dust and occasional condensation — typical for a motor control centre in a cement plant or sawmill, not just a climate-controlled switchroom.
Wiring terminals and conductor sizing
Main circuit terminals accept stranded wire 2x (1.5... 25 mm²) — that covers everything from a 4 mm² motor feed up to a 25 mm² supply cable for the full 63 A rating. Screw-type terminals on the main current circuit — no cage-clamp or push-in on the power side. Torque the screws to the value on the nameplate; the clamping points are dual (front and back) so you can loop through or terminate two conductors per pole. Maximum motor cable length is 300 m — above that, the cable capacitance can cause the thyristors to self-trigger on the off half-cycle. For long runs, add an output reactor or keep the cable below this limit.