# Question: What controls the speed of an AC motor?

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An AC motor controller is known as the device that controls the speed of the AC motor. An AC controller can also be referred to as a variable frequency drive, adjustable speed drive, frequency converter and more.

## What controls the motor speed?

The rotating speed of an electric motor depends on two factors: its physical construction, and the frequency (Hz) of the voltage supply. Electrical engineers select the speed of a motor based on the needs of each application, similar to how the mechanical load determines the horsepower required.

## How do you change the speed of an AC motor?

AC motors are constant speed devices but their speed can vary if you change the input voltage or frequency or the windings that make the motor rotate. The most common and efficient way of changing the speed is to vary the frequency by using an inverter as the power supply.

## How do you control the speed of a 3 phase AC motor?

Speed Control of Three Phase Induction Motor

1. V / f control or frequency control.
2. Changing the number of stator poles.
3. Controlling supply voltage.
4. Adding rheostat in the stator circuit.

## How do you slow the speed of a motor?

A couple of things you can do:

1. Use gears to change ratio of speed, which is what you’re going to do. …
2. Use a stepper motor, which are commonly used for high-torque, low RPM applications.
3. Find some sort of PWM control circuit to slow it down, although you probably won’t be able to get it down to 5-10RPM.

## How do you control the RPM of an electric motor?

Thus, the speed of a DC motor can be controlled in three ways:

1. By varying the supply voltage.
2. By varying the flux, and by varying the current through the field winding.
3. By varying the armature voltage, and by varying the armature resistance.

## How does an AC motor speed control work?

As previously stated, AC controllers convert an input AC frequency into a DC current that simulates an AC frequency, which can then be set by the user, thus controlling the speed of the motor. This is accomplished using three main components: a rectifier, an inverter, and a DC circuit that connects the two.

## What controls the speed of a 3 phase motor?

Speed of three phase motor depend upon frequency of alternate current and number of magnetic pole in stator winding. Variable frequency drive VFD is the best way to control the speed of three phase motor. this device can vary the frequency of alternate current. Depending upon the load they are available.

## Can I use a potentiometer to control AC motor speed?

Brushed DC or universal can be controlled with a potentiometer. AC and brushless DC motors can’t be controlled that way. They require a change in frequency, not a change in voltage. If the motor is single phase, with a starting winding, and you are using a frequency varying controller, you can’t vary things that much.

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