175L3718
by Danfoss
The 175L3718 is an AC variable frequency drive engineered by Danfoss for the VLT 3000 Variable Speed Drives series. In an automation cell it converts fixed-frequency three-phase mains power into a controllable output that matches motor demand, allowing speed control without mechanical throttling. The unit forms the interface between the plant’s PLC signals and a 3-phase induction motor, so it governs acceleration, deceleration, and steady-state torque while maintaining line-side power factor. As part of this series, it supports standard cabinet mounting and interacts with fieldbus modules offered by the manufacturer.
Electrical capacity is defined by a rated output of 125 HP and a continuous phase current of 168 A. Within the specified ±10 % line window the converter draws a maximum of 167.2 A and can deliver 185 A for 60 s to cover short overloads. Apparent power peaks at 116 kVA, while conversion efficiency reaches 0.96 at full load so only 4 % of input power is lost as heat. The drive produces output frequencies up to 120 Hz, letting motors run at double synchronous speed when mechanical limits permit. Acceleration profiles are shaped by a programmable ramp that extends to 3600 s, and upstream protection is provided by a 250 A pre-fuse coordinated with the semiconductor bridge.
Installation factors are addressed by a permitted motor lead length of 1000 ft and an output terminal that accepts conductors up to 500 kcmil. At maximum loading the inverter dissipates 910 W, a thermal figure that dictates enclosure airflow when the ambient temperature reaches the series limit of 40 °C. The chassis passed a vibration test of 0.7 g, supporting placement on machines with moderate dynamic forces, and its transport mass is 464 lb, which influences cabinet bracing and lift planning. Voltage tolerance remains ±10 % across this range, and the model’s efficiency assists in maintaining stable heat rise during prolonged duty.
