Motor Pole Count
A permanent magnet has two poles, but motors can be wired so their magnetic field has a higher number of poles. The pole count of a motor is the number of permanent magnetic poles, north and south, on the rotor. There is always the same number of north and south poles on the rotor. For example, in a 6 pole motor, there are 3 north poles and 3 south poles. This motor would also be considered a 3 pole-pair motor.
Benefits of Motor Pole Count
Benefits to having a high pole count motor include:
- Maximized inner diameter (ID) to outer diameter (OD) ratio
- Reduced weight
- Higher frequency cogging torque (related to slotted motors)
- Higher motor efficiency
Disadvantages of High Motor Pole Count
Disadvantages to having a high pole count motor include:
- Higher eddy current losses
- Increased frequency-dependent hysteresis losses
- Higher servo drive current loop bandwidth
- Reduced maximum speed
Also Read: Difference Between 2 Pole And 4 Pole Motor
4 Pole vs 6 Pole
A 4 pole motor has four magnetic poles with a north-south configuration. It gives a high speed because of the fewer poles. It delivers a high rpm and low torque when compared to a 6 pole motor.
A 6 pole motor uses six magnetic poles with a north-south-north-south configuration. It gives less speed because of the high pole number. 6 pole motors generate high torque and low rpm when compared to both 4 pole and 2 pole motors.
| Basis of Factors | 4 pole motor | 6 pole motor |
| Configuration | Has 4 magnets with north-south configuration | Has 6 magnets with north-south-north-south configuration |
| Speed | High | Low |
| Efficiency | More | Less |
| Work output | Less work output, not suitable for heavy-duty | More work output, best for heavy-duty |
| Vibration and Noise | Produces relatively much noise | Produces Relatively less noise |
| Servicing and maintenance | High maintenance | Easy Maintenance |
| Price | Budget-Friendly | Costly |
Also Read: Difference Between Bar magnet And Solenoid