# How is motor pole count calculated?

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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 do you count motor 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 12 pole motor, there are 6 north poles and 6 south poles. This motor would also be considered a 6 pole-pair motor.

## How do you tell if a motor is 2 pole or 4 pole?

If the machine is not to be or cannot be opened or it is hermetically sealed, then see the name plate details. For a 50 Hz (60 Hz) machine if the rated speed is just lower than 3000 rpm (3600 rpm) then it corresponds to 2-poles, if just lower than 1500 rpm (1800 rpm) it corresponds to 4-poles etc.

## How many RPM is a 8 pole motor?

To satisfy consumers’ desires for quieter motors, manufacturers have developed eight-pole motors. These operate at 900 rpm (unloaded) and approximately 800 rpm under load. They are being used in applications where customers expect quieter operation, such as room air conditioners and outdoor heat pump applications.

## How is motor RPM calculated?

How to Calculate Motor RPM. To calculate RPM for an AC induction motor, you multiply the frequency in Hertz (Hz) by 60 — for the number of seconds in a minute — by two for the negative and positive pulses in a cycle. You then divide by the number of poles the motor has: (Hz x 60 x 2) / number of poles = no-load RPM.

## How many rpm is a 4 pole motor?

Considering a 60 Hz power source, at what speed does a four-pole synchronous motor run? The correct answer is B, 1800 revolutions per minute (RPM).

## What is the difference between 2 4 and 6 pole motors?

On an induction motor, the number of poles determines the speed given the frequency of the power. For a 2 pole motor, at 60hz, it will spin 60 times a second, or 3600rpm. For a 4 pole motor, the speed is halved – 1800 rpm, 6 pole, 1200 rpm and so on.

## How is motor torque calculated?

To calculate load torque, multiply the force (F) by the distance away from the rotational axis, which is the radius of the pulley (r). If the mass of the load (blue box) is 20 Newtons, and the radius of the pulley is 5 cm away, then the required torque for the application is 20 N x 0.05 m = 1 Nm.

## How many RPM is 60 Hz?

The speed of 60 Hz 2-pole synchronous generator is 3,600 RPM.

## What is 120 in motor speed formula?

120 is the number of zero crossings per second in a 60hz system. To put it another way, it’s the number of voltage/current peaks per second. This determines the frequency of the torque peaks and so how often the stator magnetically pushes on the rotor.

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## What is the RPM of 1 hp motor?

1 HP Single Phase Electric Motor, For Industrial, Speed: 1440 Rpm.

## How do you calculate kW to RPM?

kW = 0.105 x Nm x rpm / 1000. Example: A three-phase induction motor can provide 144Nm at 1480 rpm. Calculate the motor rating in kilowatt.