Product Description:

Danfoss manufactures the 136G7341, a soft starter in the MCD Soft Starters series. The unit is mounted between the mains supply and an AC motor and progressively increases line voltage, thereby reducing inrush and mechanical stress during start and stop cycles. Within automated HVAC assemblies, this controlled transition helps extend motor life and lowers the peak demand seen by upstream circuit protection. The design belongs to Danfoss's low-voltage VLT soft-starter product group and serves as a space-saving alternative to bulky electromechanical starters. That operating method is useful on fans, pumps, and similar loads where a sudden full-voltage start can create abrupt torque transfer.

The unit is engineered for three-phase power networks. A built-in internal bypass contactor transfers the current path once the motor reaches full speed, limiting heat dissipation in the thyristors. Control electronics are energized from a 24 V AC/DC supply, allowing the starter to be integrated into standard low-voltage control panels. The main power circuit is rated for 171 A, a capacity matched to induction machines up to 100 hp on 480 V systems under normal duty. The unit uses Frame Size 2, which sets the mounting footprint and terminal spacing. The enclosure has an IP00 rating, so the device must be installed inside a protected cabinet to reduce accidental contact and exposure to airborne contaminants.

Under IEC AC53b test conditions, the unit sustains 170 A for the specified start profile, which supports applications that require several controlled starts per hour. Insulation coordination uses a rated impulse voltage of 6 kV and a basic insulation level of 690 V AC, which establish the minimum clearances and the selection of upstream overvoltage protection. Two programmable relay outputs are provided, and the primary contact can switch up to 10 A at 250 V AC for auxiliary fans, contactors, or alarm circuits without external interposing relays.