14 pole 12 slots vs 16 pole 18 slots BLDC Motors

In BLDC ceiling fans, the 12-slot/14-pole and 18-slot/16-pole configurations use concentrated windings. The 12-slot design is cheaper to manufacture and produces less cogging torque, while the 18-slot option provides smoother, more consistent torque. Both deliver the same 50–65% electricity savings compared to normal AC fans.

Key Comparison

·         12-Slot / 14-Pole Motor:

 

o    Cost & Production:

Requires less copper wire and is faster to wind, making it the more affordable option.

 

o    Efficiency:

Can sometimes suffer from slightly more vibration (cogging torque) depending on the magnet grade.

 

·         18-Slot / 16-Pole Motor:

 

o    Smoothness:

The higher number of slots and poles creates a more even magnetic field, resulting in quieter operation.

 

o    Torque:

Offers higher starting and running torque, allowing for larger sweep areas or heavier blade designs.

 

o    Cost:

More complex winding and manufacturing processes make these fans slightly more expensive.

 

Winding Data & Calculations

If you are repairing or rewinding either motor, the configuration directly affects your turn counts and wire gauges.

·         12-Slot Fan:

Typically uses a fractional slot concentrated winding pattern (like 14 + 14 coils). Coil turns generally sit between 300 - 400 turns per coil using 35 or 36 SWG copper wire.

 

·         18-Slot Fan:

Requires more coils (often 18 + 18) distributed across the stator. Turns per tooth typically range from 25 - 35 turns in low-voltage designs, up to 300+ turns per coil depending on stator thickness and operating voltage.

For reverse-engineering motor designs or calculating turns-per-tooth for your specific application, you can utilize the BLDC Ceiling Fan Winding Calculator. To read further on the Finite Element Method (FEM) analysis measuring cogging torque and winding factors for both designs, refer to the IJIST Research Article.