What we put on fans: AC10 or FC51, sometimes Delta
A fan is a quadratic load: torque rises with the square of speed and power with the cube. Drop the speed in half and consumption falls 8x. So for supply/exhaust ventilation, smoke extractors, and cooling towers we pick the cheapest scalar V/f drive in ND (Normal Duty) mode. In stock the regulars are Veichi AC10 1.5-22 kW as the baseline, Danfoss FC51 for HVAC projects in shopping centers and warehouses (built-in PID plus sleep mode), Delta VFD-EL for cheap utility hoods. We see the 30-50% savings vs direct-on-line on the quarterly bills of our retail-mall customers.
First question: quadratic V/f or linear
In the VFD settings we switch on "Pump/Fan" or "Quadratic V/f" mode. It is a separate menu item on every AC10/FC51/GD20. The mode lowers voltage faster than frequency and adds another 10-15% savings on top of stock V/f. Second question: do you need an EMC filter, class C2 (residential buildings, medical sites) or C3 (industrial). On AC10/AC310 the filter is already built in. Third: do you need Flying Start after a power dip, mandatory on fire smoke extractors. Fourth: pre-magnetization mode for big fans from 22 kW upward, otherwise inrush current is the same as direct-on-line. Warranty 12-24 months, shipping from Kyiv in 1-3 days.
Popular brands for fan applications
Most common options are Veichi and Delta Electronics. For advanced HVAC projects, Schneider Electric and Danfoss are also used.
Selection by key specs
Quick links: 2.2 kW, 3 kW, 5.5 kW, 7.5 kW, 11 kW.
FAQ
Is scalar mode acceptable for fan loads?
Yes, in most fan applications where high low speed torque is not required.
How to reduce fan noise with a VFD?
Set proper minimum frequency. Acceleration time. PWM carrier frequency.
When is PID needed?
When static pressure or airflow must be controlled by sensor feedback.
Warranty and support
We provide sizing assistance. Commissioning support. Technical consulting. Delivery across Ukraine and official warranty.
