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Synchronous motors can achieve efficiencies of >90% in some cases and are generally more energy-efficient than induction motors.

## How do you calculate the efficiency of a synchronous motor?

The motor efficiency excluding field and stator losses, is 95% and XS = 2.5 Ω. Calculate (i) mechanical power developed (ii) armature current (iii) back e.m.f. (iv) power angle and (v) maximum or pull-out torque of the motor. (iii) Applied voltage/phase = 440/ 3 = 254 V.

## What is efficiency of synchronous generator?

The study showed that the efficiency of single-phase synchronous generating set of low power is small. The maximum one was **16.1%**. The highest value of efficiency is achieved at the load with an output power close to the rated power of generator.

## Which is more efficient induction or synchronous motor?

The armature winding of the synchronous motor is energized from an AC source and its field winding from a DC source. The stator winding of Induction Motor is energized from an AC source. … The **synchronous motor** is more efficient than an induction motor of the same output and voltage rating.

## What is the power factor of a synchronous motor?

Synchronous motors are designed to operate at **unity (1.0) power factor or 0.8 leading power factor**. By varying the DC excitation of the motor, the power factor of the motor can be varied widely. Overexcited synchronous motors operate at leading power factor and provide reactive kVAR-like capacitors.

## What is the efficiency formula?

Efficiency is often measured as the ratio of useful output to total input, which can be expressed with the mathematical formula **r=P/C**, where P is the amount of useful output (“product”) produced per the amount C (“cost”) of resources consumed.

## Why are synchronous motors more efficient?

Synchronous motors generally have a higher power density than induction motors of comparable size, allowing them to provide more power at a smaller volume. … Synchronous motors can achieve **efficiencies of >90%** in some cases and are generally more energy-efficient than induction motors.

## What is the formula for synchronous speed?

The synchronous speed of an AC motor is determined by the frequency of the source and the number of poles. The RPM is calculated by **multiplying the frequency times 60 and dividing by the number of pairs of poles**. This was explained in Chapter 6. Some motors are designed to operate at synchronous speed.

## What is the main disadvantage of synchronous motors?

Disadvantages or Demerits:

Synchronous motors **requires dc excitation which must be supplied from external sources**. **Synchronous motors are inherently not self starting motors** and needs some arrangement for its starting and synchronizing. The cost per kW output is generally higher than that of induction motors.

## What 3 things are needed for an induction motor to work?

A 3-phase induction motor includes two essential components namely **the stator & the rotor**. In this motor, the stationary part is the stator whereas the rotating part is the rotor. In this motor, the load is connected to the shaft. Three-phase armature winding can be wound over the stator.

## 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.