# Which synchronous motor will be smallest in size?

Contents

Which synchronous motor will be smallest in size ? (D) 10 HP, 375 rpm. Explanation: Q15.

## What is synchronous motor drive?

High-power variable-speed synchronous motor drives are widely used in industry. … The synchronous motor drive is often used in applications where a high dynamic performance is required, such as rolling mills and mine hoists.

## Are synchronous motors AC or DC?

In a synchronous motor, AC power is supplied to the stator to generate a rotating magnetic field. DC power is supplied to the rotor which results in discrete North (N) and South (S) poles.

## What is called synchronous speed?

: a definite speed for an alternating-current machine that is dependent on the frequency of the supply circuit because the rotating member passes one pair of poles for each alternation of the alternating current.

## Why is it called synchronous speed?

The synchronous speed is the speed of the revolution of the magnetic field in the stator winding of the motor. … Thus, an AC machine in which the rotor moved at a speed and built a constant relationship between the frequency of the voltage in the armature winding and the number of poles is called a Synchronous Machine.

## How do you know if a motor is synchronous?

The speed of the rotating stator field is called the synchronous speed. The frequency of the power supply and the number of poles of the machine determine the synchronous speed. A synchronous motor is one in which the rotor turns at the same speed as the rotating magnetic field in the stator.

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## What are the advantages of synchronous motor?

The advantages of the synchronous motor are the ease with which the power factor can be controlled and the constant rotational speed of the machine, irrespective of the applied load. Synchronous motors, however, are generally more expensive and a d.c. supply is a necessary feature of the rotor excitation.

## How can synchronous motor be stopped?

The methods that are employed for Braking of Synchronous Motor are:

1. Regenerative braking while operating on a variable frequency supply.
2. Rheostatic braking.
3. Plugging.

## What is self control of synchronous motor?

In self controlled mode, the supply frequency is changed so that the synchronous speed is same as that of the rotor speed. Hence, rotor cannot pull-out of slip and hunting eliminations are eliminated. For such a mode of operation the motor does not require a damper winding.