Product Description:

The VLT 6122 is an HVAC variable-speed drive produced by Danfoss and supplied under the VLT 6000 HVAC Drives series. It regulates induction motor speed in fan, pump, and compressor circuits so building automation systems can match airflow or fluid flow to demand while reducing electrical consumption. During fast ramps, the drive maintains 100% acceleration torque to reach the setpoint quickly.

It supplies a typical shaft output of 90 kW, providing continuous mechanical power for large air-handling units and primary chilled-water pumps. The true input power factor of 0.90 keeps reactive demand on the facility transformer low. A conversion efficiency of 0.98 limits thermal losses and reduces enclosure ventilation requirements. The power section withstands a prospective short-circuit current of 100,000 A, so it can be connected near high-capacity switchgear when coordinated with suitable upstream protection. For integration with building management controllers, the standard serial interface is RS-485. Four selectable serial protocols allow supervisory software to read speed, operating status, and energy counters.

The inverter can deliver 160% breakaway torque for 0.5 seconds to overcome static friction in long belt drives and other demanding loads. A starting torque reserve of 110% for 1 minute follows, while a continuous overload margin of 110% accommodates brief process spikes without tripping the drive. Upstream protection permits a maximum pre-fuse size of 250 A, supporting appropriate coordination with the incoming electrical supply. The input stage tolerates a line voltage imbalance of ±3.0% of the rated supply voltage, helping keep the DC link stable when one phase sags. Cabinet layouts must leave at least 225 mm of unobstructed space above the heat sink to maintain cooling airflow. Adequate clearance allows heated air to leave the enclosure and helps prevent excessive temperatures during sustained operation.