In this post, we are learning the difference between the two types of alternating currents (AC) motor. These two AC motors are-
- Synchronous motor and
- Induction motor.
If you are doing preparation for the exam, viva, or interview, you will be asked questions- synchronous vs induction motors. These are very important topics in electrical engineering.
Many times you will be asked to compare these two types of motors.
Here, I’m comparing synchronous motor and asynchronous motor with their specifications, functions, applications, and examples.
Note: Induction motor is called the ‘Asynchronous Motor‘.
Difference between Synchronous and Induction Motors
Let’s study the comparison between both AC motors in tabular form.
| # | Content | Synchronous Motor | Induction Motor |
| 01 | Definition [What is a synchronous & Induction motors] | The electromagnetic motor which converts electrical energy into mechanical work at constant speed is called as a ‘Synchronous Motor’. | The electromagnetic motor which converts electrical energy into mechanical work at variable speed is called as a ‘Induction Motor’. |
| 02 | Motor Speed | Synchronous motor runs at the synchronous speed. | Induction motor runs at the non-synchronous speed. |
| 03 | Principle | The synchronous motor works on the principle of the ‘Magnetic Locking’. | The induction motor works on the principle of ‘Electromagnetic Induction’. |
| 04 | Starting Position | It is a non-self starting motor. | It is self-starting the motor. (especially three-phase induction motor) |
| 05 | Connected Supply (AC and DC) | It consists of two main parts- the stator and rotor. Stator connects with the three-phase AC supply and Rotor connects with the DC supply respectively. | Similarly, it also consists of two main parts- the stator and rotor. The only Stator connects with the three-phase AC supply. |
| 06 | Excitation System (DC source for rotor) | The synchronous motor requires the DC excitation system (or prime mover) to start the motor (i.e. for the rotor rotating). | The induction motor does not require an excitation system to start the motor. |
| 07 | Construction | The construction of the synchronous motor is very difficult. | The construction of the induction motor is relatively easy. |
| 08 | Relative Motion | For Synchronous motor, relative motion is not required in between the stator and rotor. | For Induction motor, relative motion is required in between the stator and rotor. |
| 09 | Slip (magnetic field vs rotor speed) | Zero slip (S=0) occurs in the synchronous motor. | The different slip occurs in the induction motor. |
| 10 | Motor Speed (in r.p.m) | It runs from 150 to 1800 rpm. synchronous of speed. | It runs at less than 1500 rpm. synchronous speed. |
| 11 | Power Factor | It has unity or lagging or leading power factor. Mostly it works on the unity power factor. | It has only a lagging power factor. |
| 12 | Efficiency (Ratio of power output & input) | The synchronous motor has more power efficiency due to the unity or leading power factor. | The induction motor is less efficient than the synchronous motor. |
| 13 | Uses | It is used for power factor correction, constant speed load service, voltage regulation of transmission line, etc. | It is mostly used in the industries. |
| 14 | Cost | This motor is costlier than the induction motor. | This motor is cheaper than the synchronous motor. |
| 15 | Maintainance | Maximum maintenance is required. | Minimum maintenance is required. |
| 16 | Example | Fan, blowing fan, a dryer is an example of the synchronous motor. | Conveyor belt, rolling mill, mixer, grinder are an example of the induction motor. |
This is all about the difference between synchronous and induction motors. Also covered the advantages and disadvantages of these two AC motors.
Hope this will help you for the preparation of the exam or interview. If you have any queries, drop me a message in the comment section below.
Related some comparisons:
- Stator vs Rotor
- Squirrel cage IM vs Slip-ring IM
- Electrical motor vs generator
- Electrical circuit vs Magnetic circuit
- Active power vs Reactive power
- Single-phase vs Three-phase AC system
- Transmission line vs Distribution line
- Analog multimeter vs Digital multimeter
Thanks for Reading!
I have completed master in Electrical Power System. I work and write technical tutorials on the PLC, MATLAB programming, and Electrical on DipsLab.com portal.
Sharing my knowledge on this blog makes me happy. And sometimes I delve in Python programming.
Excellent. Very easy to understand the way you compare both motors.
Gilmar Correa, Thank you very much 🙂
Thanks for the Excellent explanation.
Please share more knowledge regarding the induction motor for an electrical Design point of view.
Sure, I will add the construction point in the comparison of both machines. Thanks, Meera Kumar!
Excellent one!
Thanks, Nikhil:)
Good Going.
Thanks 🙂
Excellent article.
Thank you, Sir 🙂
Great, got something new mam.
Thank you very much.
Amazing article. I always thought mixers and grinders used universal motors.
Thanks, Mathew Varghese. A single-phase induction motor is used for the mixers and grinders.
Great source of knowledge please share as much as you can. Thanks!
Thank you so much, Mohammed Imran. Definitely, I will try to publish and share more tutorials and useful technical kinds of stuff.
You are doing smart job to give simple understanding electrical terms keep it up.
Thanks, Sanket. 🙂
Thanks
You’re welcome 🙂
wow….. great job
Thanks, Nifosam.
Dear Ms. Dipali Chaudhari,
Thank you for explaining the differences between Induction motors & Synchronous motors in simple terms. Keep up the good work.
Rao Kattoju
Thank you very much, Veerabhadra for your kind words. I am promising, will share more posts like this. 🙂
Thank you ,very much for good work.
Glad to see your comment.