Table of Contents
What is the advantage of more poles in motor?
Benefits of Motor Pole Count Maximized inner diameter (ID) to outer diameter (OD) ratio. Reduced weight. Higher frequency cogging torque (related to slotted motors) Higher motor efficiency.
Is more poles on a motor better?
More poles result in a lower motor speed: if all other factors are equal, a 4-pole motor will rotate at half the speed of a 2-pole motor. A 60 Hz power supply changes polarity 60 times per second, and a two-pole motor will spin at 3,600 rpm when connected to this source. A four-pole motor will only rotate at 1,800 rpm.
What speed is an 8 pole motor?
| Approximate Electrical Motor Speed (rpm) | ||
|---|---|---|
| No. Poles | Speed with Rated Load | Synchronous Speed (no Load) |
| 4 | 1725 | 1500 |
| 6 | 1140 | 1000 |
| 8 | 850 | 750 |
Why does more Poles make a motor slower?
The physical size, weight and cost of a motor are more closely related to its torque rating than to power its power rating. Not accounting for slippage, the rotor will move one pole-pair every cycle of the AC current. So the more poles you have, the more cycles it take to complete a full revolution.
How is the number of poles in an AC motor related to the speed of the motor?
The number of poles, combined with the ac line frequency (Hertz, Hz), are all that determine the no-load revolutions per minute (rpm) of the motor. So, all four-pole motors will run at the same speed under no-load conditions, all six-pole motors will run at the same speed, and so on.
What determines the number of poles in a motor?
When selecting a three phase motor, the number of poles is chosen to achieve the speed of rotation that you require. The formula is n = 60 x f /p where n = synchronous speed; f = supply frequency & p = pairs of poles per phase. The actual running speed is the synchronous speed minus the slip speed.
How fast is a 4 pole motor?
around 1800 rpm
Two pole AC motors operating at 60 Hz will always run at approximately 3600 rpm, and four pole AC motors will have speeds around 1800 rpm.
How can we increase the RPM of motor?
Increasing the speed can be achieved by increasing the supply frequency as the speed and frequency are directly proportional; however, there are two constraints. The first is the saturation of the magnetic circuit, but this issue can be significantly avoided by keeping the V/f ratio constant.
What is the difference between a 4 pole and an 8 pole motor?
8 poles motor has 8S and 8N poles. The frame size of the motor increase with an increase in the number of poles. The synchronous speed of the motor is inversely proportional to the number of poles. The synchronous speed of the 4 poles and 8 poles motor is 1500 RPM and 750 RPM respectively.
Which is stronger 6 pole or 8 pole?
6 pole Vs 8 pole motor, does more poles make it stronger?? I need and would appreciate some advice. I want to put a three phase motor and a VFD on a cold-saw that currently has a single phase motor at 940 RPM. I also want to have a little more power so I’ll go from .93kW to 1.1kW or even possiblly 1.5Kw.
What is no load speed on 6 pole motor?
No load speed for a 50Hz 6pole motor will be 1000RPM and 8 pole is 750RPM (synchronous speed) and will “slip” down as torque requirements increase. The input current rating is also at the KW rating and will be less at no load.
What is the concept of Poles in induction motor?
At 50Hz, an induction motor – say 500Kw to 2Mw or there abouts. If you have a pump that wants to run at around 1000 rpm you could use a gearbox or pulley belt system. Or you could use a 6 pole motor which is directly 1000 rpm (less slip). The 6 pole motor will be quieter, shorter in length, larger in diameter.