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4 Types of DC Motors and Their Characteristics
4 Types of DC Motors and Their Characteristics (on photo: Incline Conveyor 72″ Long 7″ Wide 90 Volt DC Motor; credit: globalmachinebrokers.com)

DC Motor Characteristics //

As you already know, there are two electrical elements of a DC motor, the field windings and the armature.The armature windings are made up of current carrying conductors that terminate at a commutator. DC voltage is applied to the armature windings through carbon brushes which ride on the commutator.

In small DC motors, permanent magnets can be used for the stator. However, in large motors used in industrial applications the stator is an electromagnet.

When voltage is applied to stator windings an electromagnet with north and south poles is established. The resultant magnetic field is static (non-rotational).

For simplicity of explanation, the stator is represented by permanent magnets in the following illustration.

DC Motor Construction
DC Motor Construction

The field of DC motors can be:

  1. Permanent magnet (Permanent magnet stator),
  2. Electromagnets connected in series (Wound stator),
  3. Shunt (Wound stator), or
  4. Compound (Wound stator).

Let’s see the basics of each type as well as their advantages and disadvantages.


1. Permanent Magnet Motors

Permanent Magnet Motors
Permanent Magnet Motor

The permanent magnet motor uses a magnet to supply field flux. Permanent magnet DC motors have excellent starting torque capability with good speed regulation. A disadvantage of permanent magnet DC motors is they are limited to the amount of load they can drive.These motors can be found on low horsepower applications.

Another disadvantage is that torque is usually limited to 150% of rated torque to prevent demagnetization of the permanent magnets.

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2. Series Motors

Series DC motor
Series DC motor

In a series DC motor the field is connected in series with the armature.The field is wound with a few turns of large wire because it must carry the full armature current.

A characteristic of series motors is the motor develops a large amount of starting torque. However, speed varies widely between no load and full load. Series motors cannot be used where a constant speed is required under varying loads.

Additionally, the speed of a series motor with no load increases to the point where the motor can become damaged. Some load must always be connected to a series-connected motor.

Series-connected motors generally are not suitable for use on most variable speed drive applications.

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3. Shunt Motors

DC Shunt Motor
DC Shunt Motor

In a shunt motor the field is connected in parallel (shunt) with the armature windings. The shunt-connected motor offers good speed regulation. The field winding can be separately excited or connected to the same source as the armature.

An advantage to a separately excited shunt field is the ability of a variable speed drive to provide independent control of the armature and field.

The shunt-connected motor offers simplified control for reversing. This is especially beneficial in regenerative drives.

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4. Compound Motors

Compound DC motor
Compound DC motor

Compound motors have a field connected in series with the armature and a separately excited shunt field. The series field provides better starting torque and the shunt field provides better speed regulation.

However, the series field can cause control problems in variable speed drive applications and is generally not used in four quadrant drives.

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DC Motor – Explained (VIDEO)

Cant see this video? Click here to watch it on Youtube.

Reference: Basics of DC Drives – SIEMENS (Download)

About Author //

author-pic

Edvard Csanyi

Edvard - Electrical engineer, programmer and founder of EEP. Highly specialized for design of LV high power busbar trunking (<6300A) in power substations, buildings and industry fascilities. Designing of LV/MV switchgears.Professional in AutoCAD programming and web-design.Present on

16 Comments


  1. Cy
    Aug 19, 2016

    The Brushed DC motor variety has a type when one turns the shaft manually it free runs with no friction or resistance at all and then another type which feels like a mild step friction/resistance as though magnets inside causing some type of resistance when the shaft passes them? Which type are these and what is the difference.


  2. KAVAN
    Jul 27, 2016

    thanks that was very helpful because i needed to do a sience project and i wanted to do DC motors because i do RC racing and i use a DC motor in it.


  3. murugan .T
    Jun 26, 2016

    not bad.improve in your presentation .


  4. ARKA CHATTERJEE
    May 02, 2016

    can you tell me what is the approx ohmic range of starting resistance of a dc motor?


  5. Uday
    Nov 08, 2015

    Very useful information in simple words understandable to all….

    Thanks for the explaination


  6. u.k.sharma
    Oct 24, 2015

    thank u,it is useful but here is not about short shunt & long shunt dc motor.


  7. usman ghani
    Oct 21, 2015

    exellent informestion


  8. rob
    Oct 14, 2015

    Can you tell me if the actual resistance value of the rotor, field and poles is critical to the operation of a DC Series wound motor and if so how it can be determined


  9. m.shivakumar
    Aug 14, 2015

    excellent information sir thank u a lot plz tell me the basics of electrical engineering sir


  10. SADGUN VAMSHIDHAR REDDY KANDI
    May 02, 2015

    This is an excellent site helping me beyond my academic studies.


  11. Jose
    Jan 16, 2015

    Could you explain me about Ethernet , mod-bus, what it is?


  12. Jose
    Jan 16, 2015

    Excellent information.
    Do you have information about squirrel cage motor?


    • Brijmohan Paliwal
      Apr 09, 2015

      Squirrel cage motor is AC motor whose rotor is made of copper rods short circuited at both ends.EMF is induced by mutual induction method.
      AC voltage is applied to stator of the motor.in turns it produces rotating magnetic field and produces starting torque to rotate the rotor of motor.


  13. PETER
    Jan 10, 2015

    Thank you, very useful


  14. Марк
    Jan 09, 2015

    In the future, you can find points of contact


  15. bharath
    Jan 08, 2015

    Nice overview of DC machines.. Wanna know about synchronous machines and DC choppers

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