**Contents**show

## Which method is used for speed control of induction motor?

By **Injecting EMF In Rotor Circuit**

Speed control of induction motor is done in this method by injecting a particular voltage in the rotor diagram. The injected voltage (emf) needs to have an equal frequency with the slip frequency. However, there is no limitation for the phase of that emf.

## Which induction motor has maximum speed?

Synchronous and full load speed of amplitude current (AC) induction motors

Speed (rpm) | ||
---|---|---|

Number of Poles | Frequency (Hz, cycles/sec) | |

Synchronous | Full Load | |

2 | 3600 | 2900 |

4 | 1800 | 1450 |

## What is the speed of a DC motor?

DC controls adjust speed by varying the voltage sent to the motor (this differs from AC motor controls which adjust the line frequency to the motor). Typical no load or synchronous speeds for an AC fractional horsepower motor are 1800 or 3600 rpm, and **1000-5000 rpm for DC fractional hp motors**.

## What are types of induction motor?

There are three basic types of small induction motors: **split-phase single-phase, shaded-pole single-phase, and polyphase**. In two-pole single-phase motors, the torque goes to zero at 100% slip (zero speed), so these require alterations to the stator such as shaded-poles to provide starting torque.

## How can we increase the RPM of induction 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.