Cooler fan blade and motor matching
The blade decides the load on the motor. Match the blade size and material to the motor and it runs for seasons; get it wrong and it burns in weeks.
Which blade for which motor
| Motor | Blade size | Blade material | Note |
|---|---|---|---|
| H-Frame 32 / 35 / 38 mm | 18 to 24 inch | Climatizer, aluminium or CRCA steel | Larger blade, larger stack |
| H-Frame 44 / 51 / 70 mm aluminium body | Large blades | Balanced metal blade | Confirm size with us |
| E-Frame 32 mm | Mid-size | As per cooler body | Confirm size with us |
| 110 Dia 28 / 32 / 41 mm | Window and personal cooler sizes | Plastic; metal only on 28 mm and above | Bush motor, keep the blade light |
| 110 Dia 18 / 19 mm Tower Motor | Tower blower wheel | Plastic | Slim motor for tower coolers |
| 89 Dia Bachcha motor | Up to 12 inch | Plastic only | No metal blades |
Not sure? Send the blade diameter, number of blades and material on WhatsApp and we will tell you the right motor before you buy.
Diameter and pitch
Load rises steeply with blade diameter and with the angle of the blades. Two blades of the same size can load a motor very differently.
Material and weight
Plastic blades are light and suit bush motors. Aluminium and steel blades move more air but need a bearing motor to carry them.
Bore and balance
The blade's bore must match the shaft, commonly half an inch. An unbalanced blade wears the bush or bearing and makes the cooler hum.
Blade terms in the trade
Blade questions
Why does a wrong fan blade burn a cooler motor?
A blade that is too large, too steeply pitched or too heavy makes the motor work harder than it is wound for. Current rises, the winding overheats and the insulation fails. This is the most common cause of a burnt cooler motor.
Can I use a metal blade on a small cooler motor?
Not on the 89 Dia Bachcha motor, which takes a plastic blade up to 12 inch only. Metal blades belong on bearing motors such as the H-Frame.
Does using the wrong blade affect warranty?
Yes. Damage from a blade outside the recommended size or material is overloading and is not covered under warranty.
What blade size fits an 18 inch cooler?
An 18 inch cooler takes an 18 inch blade, normally on an H-Frame 32 mm motor. Check that the blade's bore matches the motor shaft.
NEXPOWER manufactures motors and motor parts. We do not manufacture fan blades; we supply Speedo blades with our motors on request. See the full blade size chart.