Overload Relays 3RB2 Solid-State Overload Relays 3RB20, 3RB21 for standard applications 1) For version with straight-through transformer up to 1000 V AC. 2) For version with straight-through transformer up to 8 kV. 3) For grounded networks, otherwise 600 V. 4) If two different conductor cross-sections are connected to one clamping point, both cross-sections must lie in the range specified. If identical cross- sections are used, this restriction does not apply.
22 Siemens · 2009 Type Size Width 3RB20 16, 3RB21 13 3RB20 26, 3RB21 23 3RB20 36, 3RB21 33 3RB20 46, 3RB21 43 S00 S0 S2 S3 45 mm 45 mm 55 mm 70 mm Main circuit Rated insulation voltage Ui V (degree of pollution 3) 690 690/10001) 1000 Rated impulse withstand voltage Uimp kV 6 6/82) 8 Rated operational voltage Ue V 690 690/10001) 1000 Type of current • Direct current • Alternating current No Yes, 50/60 Hz ±5 % Current setting A 0.1 ... 0.4 to 3 ... 12 0.1 ... 0.4 to 6 ... 25 6 ... 25 and 12.5 ... 50 12.5 ... 50 and 25 ...
100 Power loss per unit (max.) W 0.05 Short-circuit protection • With fuse without contactor • With fuse and contactor See Catalog LV 1, "Selection and ordering data" See "Technical specifications" (short-circuit protection with fuses for motor feeders) Protective separation between main and auxiliary con- V ducting path acc.
to IEC 60947-1 (degree of pollution 2) 6903) Connection for main circuit Connection type • Terminal screw • Tightening torque Nm • Conductor cross-sections (min./max.), 1 or 2 conductors - Solid mm2 - Finely stranded without end sleeve mm2 - Finely stranded with end sleeve mm2 - Stranded mm2 - AWG cables, solid or stranded AWG - Ribbon cable conductors mm (number x width x thickness) Screw terminals with box terminal Pozidriv size 2 Allen screw 4 mm 0.8 ... 1.2 2 ... 2.5 3 ... 4.5 4 ... 6 2 × (0.5 ... 1.5)4), 2 × (0.75 ... 2.5)4) 2 × (1 ... 2.5)4), 2 × (2.5 ... 6)4) 2 × (1 ... 16) 2 × (2.5 ... 16) -- 2 × (0.5 ... 1.5)4), 2 × (0.75 ... 2.5)4) 2 × (1 ... 2.5)4), 2 × (2.5 ... 6)4) 2 × (1 ...
16)4), 1 × ( 1 ... 25)4) 2 × (2.5 ... 35), 1 × (2.5 ... 50) -- 2 × (max. 25), 1 × (1 ... 35) 2 × (10 ... 50), 1 × (10 ... 70) 2 × (18 ... 14) 2 × (14 ... 10) 2 × (max. 4), 1 × (18 ... 2) 2 × (10 ... 1/0), 1 × (10 ... 2/0) -- 2 × (6 × 9 × 0.8) 2 × (6 × 9 × 0.8) Connection type • Terminal screw • Tightening torque Nm • Conductor cross-section (min./max.) - Finely stranded with cable lug mm2 - Stranded with cable lug mm2 - AWG cable, solid or stranded, with cable lug AWG - With connecting bar (max. width) mm Busbar connections -- M 6 × 20 -- 4 ... 6 -- 2 × 70 -- 3 × 70 -- 2/0 -- 12 Connection type Diameter of opening mm Straight-through transformers -- 15 18