175Z4881 by Danfoss

The 175Z4881 is an AC variable-frequency drive built by Danfoss for the VLT 6000 HVAC Drives series. Classified as an HVAC drive, the unit is intended to vary the speed of three-phase fan, pump, and compressor motors so that airflow or chilled-water output matches building load demands. When installed in mechanical-room control panels, it helps reduce energy use and limits startup stress compared with constant-speed starters. This makes the drive suitable for large building systems that need stable motor control across changing operating conditions.

Electrically, the inverter delivers 55 kW and 75 HP of continuous motor power, which suits large air handlers and cooling towers in HVAC systems. It accepts a supply range of 380-460 VAC, allowing direct connection to common 50 Hz and 60 Hz distribution networks. The aluminum housing uses a compact IP20 format that provides finger-safe access while relying on the surrounding cabinet for added dust and water protection. The drive is supplied as a Standard unit, providing core VLT control functions without optional pump-sequence or cascade cards. This arrangement keeps the feature set focused on general building-service motor control.

Operator interaction occurs through the detachable keypad supplied with an LCP, which stores parameter sets and displays current draw and fault codes in real time. An internal EMI network meets Class A1 and B filter requirements, so additional line chokes are unnecessary in most installations. The circuit boards are supplied without a coating, so the installation area should remain suitable for unprotected electronics. Both the application expansion slot and the fieldbus bay are shipped without installed options, leaving the drive to communicate through hard-wired terminals or an external gateway. Temperature-controlled fans run only when needed, which reduces audible noise during light-duty operation and helps limit unnecessary fan wear.