Choose single phase if your site has only a 220 V supply, and three phase if 415 V is available, especially for larger coolers. Add a VFD if the cooler will run long hours and you want speed control. Always fit a phase preventer on a three-phase cooler to protect the motor.
What our duct coolers offer
| Model | Motor | Single phase 220 V | Three phase 415 V |
|---|---|---|---|
| 18,000 CMH | 1.1 kW | Yes | Yes |
| 22,000 CMH | 1.5 kW | Yes | Yes |
| 25,000 CMH | 2 kW | Yes | Yes |
| 30,000 CMH | 3 kW | Yes | Yes |
| 50,000 CMH | 4.5 kW | No | Yes |
Single phase
- Works on the supply most shops, small workshops and offices already have
- Simple to connect
- Best for the smaller models and for one or two coolers
Three phase
- The standard supply in factories and warehouses
- Shares the load evenly across three lines, which suits larger motors
- Needed for the 50,000 CMH model
- Must be protected against phase failure
Why a phase preventer matters
If one of the three phases drops out or the voltages go out of balance, the motor keeps trying to run, overheats and burns out within minutes. A controller with a phase preventer cuts the power first. Our 1-year motor warranty applies only when one is fitted.
What a VFD does
A variable frequency drive changes the motor speed smoothly from a wall display or remote.
- Lower power use when full airflow is not needed, such as mornings, evenings and mild days
- Less noise at reduced speed
- Softer starts, which are easier on the motor and belt-free fan
A VFD costs more at the start; it pays back fastest on coolers that run many hours a year. See the VFD kit, available from 1.1 to 4.5 kW.
Quick guide
| Your site | Choose |
|---|---|
| Shop or small workshop, 220 V only | Single-phase 18,000 to 25,000 CMH |
| Factory with 415 V | Three phase with phase preventer |
| Long running hours, changing weather | Add a VFD |
| Very large floors | Three-phase 50,000 CMH |
Frequently asked questions
Can an industrial cooler run on single phase?
Yes. Our 18,000 to 30,000 CMH coolers are available in single phase; the 50,000 CMH model is three phase only.
Is a VFD necessary for an air cooler?
Not necessary, but it saves power and noise when the cooler runs below full speed for many hours.
Why does a three-phase cooler need a phase preventer?
Because a phase failure makes the motor overheat and burn out; the preventer cuts power in time.