Premium Membership. Study specialized technical articles, electrical guides, and papers. 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. For simplicity of explanation, the stator is represented by permanent magnets in the following illustration.
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. 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. Series-connected motors generally are not suitable for use on most variable speed drive applications. 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.
Types of DC Motor
The shunt-connected motor offers simplified control for reversing. This is especially beneficial in regenerative drives. 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.Like DC generators, there are different types of DC motors characterized by the connections of the field winding in relation to the armature. They are. DC Shunt Motor The current through the shunt field winding is not the same as the armature current.
Shunt field windings are designed to produce the necessary m. A series-wound DC motor is one type of dc motor in which the field winding is connected in series with the armature.
DC Series motor Therefore, the series field winding carries the armature current. When the shunt field winding is directly connected across the armature terminals, it is called a short-shunt connection.
When the shunt winding is so connected that it shunts the series combination of armature and series field, it is called a long-shunt connection. Your email address will not be published. Remember Me. Not a member yet? Register now. Want to become an instructor?
Are you a member? Login now. DC Motor. A shunt-wound motor is a type of dc motor in which the field winding is connected in parallel with the armature. DC Shunt Motor. DC Series motor.
Therefore, a series field winding has a relatively small number of turns of thick wire and, therefore, will possess a low resistance. The compound-wound DC motor which has two field windings: One winding is connected in parallel with the armature The other winding is connected in series with it.In my previous article Click here to read the article I have discussed that DC motors are still used where we want speed control.
Today we will see the different types of DC motors based on the arrangements of Filed and Armature windings. Before we jump into types of DC motors we should understand the equivalent circuit of a DC motor. As we know, there is a Field Winding and an Armature Winding. The Field winding will have inductance and resistance, therefore we can represent Field Winding as an inductor and resistor.
There is an internally generated voltage Motional EMF in Conductor in Armature Winding; therefore, we can represent it as a voltage source. Further, there will be resistance offered by Armature Winding. The equivalent circuit can be given as. You may think that there should be Inductance offered by Armature Winding. It is true that there will be inductance, and there will be a voltage drop at it. The voltage drop of an inductor depends on the rate of change of current. In steady-state, the rate of change of current is negligible so the voltage drop will be negligible.
Therefore, it is not shown in the circuit. The Field Inductance is shown because the Field Resistance is varied for controlling the speed of the motor. It changes the current in the winding. Therefore, the rate of change in current will not be negligible this time. So, therefore, the Field Inductance is shown in the circuit. The internally generated voltage Motional E. F is directly proportional to flux generated and the speed of armature Rotor. The major types of dc motors classified according to the arrangement of Armature and Field winding are given below.
Therefore, there are two sources, one for Armature and the other for Field Winding. Therefore, there is only one source from which the current is divided into the Armature branch and Field branch. Consider the following circuit.
In both the equations are identical, only the magnitude of armature current is different, which can be controlled by applied Voltage V T. In the Separately Excited motor, it is very clear that the Field and Armature current are independent of each other.
While in Shunt motor, the Field Winding and Armature are parallel. In a parallel connection, the current is independent of the resistance in other branches. The current depends on the branch resistance and applied voltage.From robotics to automobiles, small and medium sized motoring applications often feature DC motors for their wide range of functionality. Because DC motors are deployed in such a wide variety of applications, there are different types of DC motors suited to different tasks across the industrial sector.
The permanent magnet motor uses a permanent magnet to create field flux. This type of DC motor provides great starting torque and has good speed regulation, but torque is limited so they are typically found on low horsepower applications. In a series DC motor, the field is wound with a few turns of a large wire carrying the full armature current.
Typically, series DC motors create a large amount of starting torque, but cannot regulate speed and can even be damaged by running with no load. These limitations mean that they are not a good option for variable speed drive applications. In shunt DC motors the field is connected in parallel shunt with the armature windings. These motors offer great speed regulation due to the fact that the shunt field can be excited separately from the armature windings, which also offers simplified reversing controls.
Compound DC motors, like shunt DC motors, have a separately excited shunt field. Compound DC motors have good starting torque but may experience control problems in variable speed drive applications. Between the 4 types of DC motors, the potential applications are numerous. Each type of DC motor has its strengths and weaknesses.
Understanding these can help you understand which types may be good for your application. To learn more about DC motors and their applications, browse our directory of DC servo drive suppliers. Sign In. There are 4 main types of DC motors: 1. Series DC Motors In a series DC motor, the field is wound with a few turns of a large wire carrying the full armature current.
Visit our other association websites.Premium Membership. Study specialized technical articles, electrical guides, and papers. Almost all modern industrial and commercial undertakings employ electric drive in preference to mechanical drive because it possesses the following advantages :. However, the above two disadvantages can be overcome by installing diesel-driven DC generators and turbine-driven 3-phase alternators which can be used either in the absence of or on the failure of normal electric supply.
Since it has high starting torque and variable speedit is used for heavy duty applications such as electric locomotives, steel rolling mills, hoists, lifts and cranes. It has high starting torque, large overload capacity and a nearly constant speed. It has high starting torque and large overload capacity. Slip ring induction motor is used for those industrial drives which require high starting torque and speed control such as lifts, pumps, winding machines, printing presses, line shafts, elevators and compressors etc.
It possesses high starting torque and its speed can be controlled over a wide range. Moreover, it has high speed at high loads. It has fairly constant speed and moderately high starting torque. Speed control is not possible.
Its operating characteristics are similar to the above motor except that it has better power factor and higher efficiency. This is really informative, and handy when you need to choose a type of electric drive.
Different types of motors and their use
It would also be really handy to give a rough price comparison of different power options, as the most cost-effective motor that delivers the drive solution is generally sought. These motors are cheap to produce, but are heavy and not all that efficient.
This option may come at a price premium though, so may not be the most appropriate. It is not covering brushless d. This article is really very helpful and a reminder of Basics those we forget with time and work area in the different areas.
Thanks a lot. Good explanation,I have got more than my expectation, your way of explanation videos is very good. Great info. There are many differences between these motor types and you really need to dig into the matter to know which one is right for you. Search for:. More Information.
However, electric drive system has two inherent disadvantages : It comes to stop as soon as there is failure of electric supply and It cannot be used at far off places which are not served by electric supply.
Related EEP's content with sponsored links. It helps you to shape up your technical skills in your everyday life as an electrical engineer. Professional in AutoCAD programming. Please provide the details in pdf from. Plz Mar 26, Industrial Contractors Winnipeg Aug 29, Almost every mechanical movement that we see today is accomplished by an electric motor.
An electric motor takes electrical energy and produces mechanical energy. Electric motors come in various ratings and sizes. Some applications of large electric motors include elevators, rolling mills and electric trains. Some applications of small electric motors are robots, automobiles and power tools.
Types of DC Motors
The function of both AC and DC motors is same i. Both AC and DC electric motors consist of a stator which is a stationary part and a rotor which is a rotating part or armature of the motor. The principle of working of an electric motor is based on the interaction of magnetic field produced by the stator and the electric current flowing in the rotor in order to produce rotational speed and torque. There are different kinds of DC motors and they all work on the same principle.
A DC motor is an electromechanical actuator used for producing continuous movement with controllable speed of rotation.
4 Types of DC Motors: An Introduction
DC motors are ideal for use in applications where speed control and servo type control or positioning is required. As mentioned earlier, any motor consists of two parts viz. Based on the configuration and construction, there are three types of DC motors: brushed motor, brushless motor and servo motor. An electromechanical energy conversion device will take electrical energy at the input and produces a mechanical energy at the output side.
There are three electrical machines that are extensively used for this task: a DC motor, an induction or asynchronous motor and a synchronous motor. Induction motor and synchronous motors are AC motors. In all the motors, the electrical energy is converted into mechanical when the magnetic flux linking a coil is changed.
An electric motor takes electrical energy as input and converts into mechanical energy.
When the electrical energy is applied to a conductor which is placed perpendicular to the direction of the magnetic field, the result of the interaction between the electric current flowing through the conductor and the magnetic field is a force.
This force pushes the conductor in the direction perpendicular to both current and the magnetic field, hence, the force is mechanical in nature. The value of the force can be calculated if the density of the magnetic field B, length of the conductor L and the current flowing in the conductor I are known. When a conductor which is carrying current is placed in a magnetic field, a force acts on the conductor that is perpendicular to both the directions of magnetic field and the current.
A DC motor consists of two sets of coils called armature winding and field winding. Field winding is used to produce the magnetic field. A set of permanent magnets can also be used for this purpose. If field windings are used, it is an electromagnet. The field winding is the fixed part of the motor or a stator. The armature winding is rotor part of the motor. The rotor is placed inside of stator. The rotor or the armature is connected to the external circuit through a mechanical commutator.
Generally, Ferro magnetic materials are used to make both stator and rotor which are separated by air gap. The coil windings inside the stator are made of series or parallel connections of number of coils.
The Copper windings are generally employed for both armature and field windings. The principle of operation of a DC motor is explained below. Principle of operation of DC Motor. Consider a coil placed in a magnetic field with a flux density of B Tesla. When the coil is supplied with direct current by connecting it to a DC supply, a current I flows through the length of the coil.
The electric current in the coil interacts with the magnetic field and the result is exertion of a force on the coil according to the Lorenz force equation.A DC motor is any of a class of rotary electrical motors that converts direct current electrical energy into mechanical energy. The most common types rely on the forces produced by magnetic fields. Nearly all types of DC motors have some internal mechanism, either electromechanical or electronic, to periodically change the direction of current in part of the motor.
DC motors were the first form of motor widely used, as they could be powered from existing direct-current lighting power distribution systems.
A DC motor's speed can be controlled over a wide range, using either a variable supply voltage or by changing the strength of current in its field windings. Small DC motors are used in tools, toys, and appliances. The universal motor can operate on direct current but is a lightweight brushed motor used for portable power tools and appliances. Larger DC motors are currently used in propulsion of electric vehicles, elevator and hoists, and in drives for steel rolling mills.
The advent of power electronics has made replacement of DC motors with AC motors possible in many applications. A coil of wire with a current running through it generates an electromagnetic field aligned with the center of the coil.
The direction and magnitude of the magnetic field produced by the coil can be changed with the direction and magnitude of the current flowing through it.
A simple DC motor has a stationary set of magnets in the stator and an armature with one or more windings of insulated wire wrapped around a soft iron core that concentrates the magnetic field. The windings usually have multiple turns around the core, and in large motors there can be several parallel current paths.
The ends of the wire winding are connected to a commutator. The commutator allows each armature coil to be energized in turn and connects the rotating coils with the external power supply through brushes. Brushless DC motors have electronics that switch the DC current to each coil on and off and have no brushes.
The total amount of current sent to the coil, the coil's size and what it's wrapped around dictate the strength of the electromagnetic field created. The sequence of turning a particular coil on or off dictates what direction the effective electromagnetic fields are pointed. By turning on and off coils in sequence a rotating magnetic field can be created. These rotating magnetic fields interact with the magnetic fields of the magnets permanent or electromagnets in the stationary part of the motor stator to create a torque on the armature which causes it to rotate.
In some DC motor designs the stator fields use electromagnets to create their magnetic fields which allow greater control over the motor. The speed of a DC motor can be controlled by changing the voltage applied to the armature. The introduction of variable resistance in the armature circuit or field circuit allowed speed control. Modern DC motors are often controlled by power electronics systems which adjust the voltage by "chopping" the DC current into on and off cycles which have an effective lower voltage.
Since the series-wound DC motor develops its highest torque at low speed, it is often used in traction applications such as electric locomotives, and trams.