It switches motor loads at up to 850 operations per hour in AC-3 duty.
The 52 a MTBF reflects a mean time between failures of 52 years under typical operating conditions — a reliability figure that justifies stocking this as a critical spare for legacy SIRIUS installations. The S3 frame size determines the physical footprint: 70 mm wide, 140 mm high, 152 mm deep, which matches the standard S3 cutout in existing panels. Coil pickup is specified at 0.8 x rated value, meaning the 21-33 V coil will pull in reliably at 16.8 V minimum — useful for long cable runs where voltage drop is a concern. The inrush peak of 2.2 A and steady-state draw of 2.4 VA at 50/60 Hz let you size the control transformer without overspecifying. Switching rates are duty-dependent: 900/h for resistive loads (AC-1), 850/h for standard motor starting (AC-3), and 200/h for plugging/inching (AC-4). If your application involves frequent reversing or jogging, the AC-4 ceiling governs the thermal limit — not the higher AC-3 number.
Main circuit accepts solid 2.5-16 mm² or stranded 6-70 mm²; auxiliary wiring takes 2x 0.5-1.5 mm² solid or 2x 0.75-2.5 mm² stranded. These are the minimum air gaps to adjacent metalwork — ignore them and you risk flashover during the 10-20 ms arcing time.