Fans that follow the building's rhythm
Office floors empty at night. Hotels swing between full and half occupancy. A VAV system is built around that change, and the fan has to follow terminal demand without wasting energy or getting noisy.
Fans built for ceiling AHUs and VAV cabinets
The ZQ and ZQL2 forward-curved centrifugal fans are made for ceiling AHUs and VAV cabinets. They pair an EC motor with a multi-blade impeller sized for the compact cabinet and lower static pressure common on commercial floors. The ZQ covers 7 to 15 inch wheels; the ZQL2 goes from 9 to 18 inches for larger central units.
Retrofitting old belt-driven units
Retrofit work is where these earn their place. An old belt-driven fan comes out of an existing cabinet and an EC direct-drive unit goes in, with no separate VFD to wire. The savings show up in both the power bill and the maintenance calendar, since belts and pulleys disappear.
Central stations and fan coil units
Central station AHUs use the YUWA plug fan. For fan coil units and small duct runs, the PP series covers 100 to 2,000 m3/h with the same EC speed control and quiet operation.
Direct from the maker
Midi Industrial owns the production line, so we can match the fan to the exact cabinet and control setup. We work with OEMs and contractors on private-label builds and can adjust wheel size and motor power for retrofit spaces that do not match a standard catalog.
Control System and PLC Connection
A VAV controller or PLC tells the fan what speed to hold as terminal boxes open and close. The built-in driver follows that signal directly, so no separate VFD has to fit in the ceiling.
|
Control Input |
Motor Terminals |
PLC Connection |
|
0-10V analog |
VSP, GND |
PLC analog output; 0V = minimum speed, 10V = full speed |
|
PWM |
PWM, GND |
PLC pulse output; 0-100% duty cycle sets speed |
|
Modbus RTU / RS485 |
RSA+, RSB- |
PLC or HMI as Modbus master; reads status and alarms, writes speed |
All three options can be wired from the same PLC cabinet. 0-10V is the simplest wiring for a single speed command; Modbus RTU is chosen when the PLC or BMS needs two-way data, run status and fault feedback.
Recommended Models and Specifications
|
Model |
Type |
Size |
Airflow m3/h |
Pressure Pa |
Power |
Temp C |
|
ZQ |
EC forward centrifugal |
7-15 in |
300-13,000 |
0-800 |
0.25-4 kW |
-25 to 45 |
|
ZQL2 |
EC/AC forward centrifugal |
9-18 in |
600-30,000 |
0-800 |
1.5-7.5 kW |
-25 to 45 |
|
YUWA |
EC plug fan |
400-630 mm |
1,000-24,000 |
0-2,500 |
1.1-7.5 kW |
-25 to 40 |
|
PP |
EC forward centrifugal |
130-180 mm |
100-2,000 |
0-250 |
0.06-0.12 kW |
-25 to 60 |
FAQ
Do I still need a separate VFD?
No. The EC motor has its controller built in. Speed control comes through 0-10V, PWM, or Modbus without an external drive.
Can these replace an old belt fan in the same cabinet?
In most cases yes. We match the new unit's footprint and airflow to the existing cabinet, so the box and ductwork stay in place.
Are they suitable for quiet office spaces?
The smooth EC ramp and multi-blade impeller keep sound low. We can supply sound data at the actual duty point so you can check it against the room spec.
Call to Action
Send the cabinet dimensions and airflow schedule. We will confirm the retrofit model and quote factory pricing.