Product Description:

The 175G5222 soft starter is manufactured by Danfoss and is part of the MCD Soft Starters series. Designed for induction motors fed from three-phase utility lines, the MCD 202 variant manages voltage ramp-up so that mechanical couplings and branch circuits experience lower transients during every start. By controlling initial torque during acceleration, it helps protect conveyor drives, pump impellers, and fan shafts from shock while simplifying the wiring that would otherwise be required for electromechanical contactor arrangements.

The power section is rated for 42 A when the three-phase mains supply is between 200–440 VAC. Under these conditions, the unit can energize motors up to 18 kW. During each start, the SCR stack permits a momentary current of 4 × FLC, and that surge can persist for 6 s to overcome static friction before the bypass closes. Once the motor reaches speed, the controller imposes an off-time of 354 s to let the semiconductors cool, a duty period that matches the compact A-frame thermal limits. Panel installation is simplified by a 30 mm DIN mounting rail slot molded into the base, allowing the soft starter to be clipped beside circuit breakers inside the cabinet.

The control circuit is energized from a low-voltage source rated at 24 VAC/VDC, and its initial draw is limited to 2 A so small auxiliary supplies can be used. The unit has an IP20 enclosure, which provides touch protection for cabinet-mounted installation. Silicon stress is quantified by an 10500 A²s I²t rating, indicating the thermal energy the SCRs can absorb during faults before tripping. Additional motor safety is provided through a 2.8 kΩ thermistor input, and the three-phase topology maintains balanced phase power so downstream overload relays receive symmetrical currents even when starting torque is intentionally reduced.