This motor is used when both a high starting torque and good speed regulation is needed. With a dc compound motor, the majority of the field is wound for a shunt field but with a few turns of series winding on top. A car may have as many as 20 dc motors to drive fans, seats, and windows. Dc compound motor definition, types, applications, equations. Apart from the basics, we had also studied the characteristics of different types of motors such as shunt, series, and compound motor. The orientation of the series flux may be such as to aid or oppose the shunt flux in the magnetic circuit. These ratios are dictated by the size of the solar cell array and are the paper deals with the calculation. Thus, in this article, we had discussed the basics of dc motor. The compound wound generators may be cumulatively compounded or differentially compounded. That is why, universal motors generally comes built into the device they. Starting characteristics of direct current motors powered by. Lathes, drills, boring mills, shapers, spinning, and weaving machines series motor. Therefore shunt motor will approximately be operated at same speed under no load and full load conditions.
Stop the bench mounted motordc generator set and turn off the variac. The dc compound motor has a greater torque than a shunt motor due to the series field. Overall characteristics of dc shunt motor falls somewhere in between these 2 extreme limits. Dc motor is mainly constructed from two main parts, the stator and the rotor as shown in fig.
Compared to the shunt motor, the series dc motor has high starting torque and poor speed regulation. Starting characteristics of direct current motors powered. Speed control of dc motor is achieved using different methods. Dc motor principle a machine that converts dc power into mechanical energy is known as dc motor. This article describes the construction of dc motor. The performance of any motor can be judged from its characteristic curves known as motor characteristics. A compound wound motor has both a series and a shunt field winding, i.
Equivalent circuit of compound excited dc motor differential compound torque t a a s a a f s f. Types of dc motors and their applications electrical4u. The characteristic of the dc generators explain the relations between the loads, excitation and terminals voltage through graph. Swinburnes test and speed control of dc shunt motor. Direct current motors are used in photovoltaic systems.
These motors are generally series wound armature and field winding are in series, and hence produce high starting torque see characteristics of dc motors here. Load characteristics of dc compound generator with differential and cumulativeconnections. The compound motor is further subdivided as cumulative compound motor and differential compound motor. These motors are only used where the variation of speed is possible. Sep 30, 2017 speed torque characteristics of dc compound motor. Compound wound dc motor or dc compound motor electrical4u. Classification of dc motor is more common than we may think. This type of generators can be used as either long shunt or short shunt compound wound generators as shown in the diagram below.
First, one is separately excited dc motor and selfexcited dc motor. In a series wound dc motor, the speed varies with load. Seeing that a compound dc motor is basically a combination of a shunt wound dc motor and a series wound dc motor, it inherently acquires, to some extent, the advantages of these two categories of motors. Universal motor construction, working and characteristics. In case of dc shunt motors, we can assume the field flux. Load characteristics of dc shunt and compound motor. That is why, universal motors generally comes built into the device they are meant to drive.
Torquespeed characteristic of a shunt or separately excited dc motor ind then, with constant v t, otherwise it affect the torquespeed curve this equation is a straight line with a negative slope. Compound motor characteristics depend upon type whether it is cumulatively compound or differential compound. It should be noted any suitable characteristic can be obtained by suitable designing of number of shunt field turns and or number of series field turns in the dc compound motor. When the direction of shunt field flux and series field flux is the same that means flux of one. Armature control for starting and for below base speed full voltage. Dc motor fault zone analysis is a vital part of any dc motor maintenance program. A synchronous motor is used to drive the dc generator throughout this experiment. Therefore, a differential compound motor is rarely used for any practical application. These are explained below for each type of dc motor.
A schematic of a speed torque characteristics of dc compound motor is shown in fig. There is no difference in the construction of dc motor and generator. Compound motor characteristics basically depends on the fact whether the motor is cumulatively compound or differential compound. Characteristics of dc motor shunt, series, and compound. In compound wound dc generators both the field windings are combined series and shunt. Pedro raposo dc voltage is applied to the armature windings through carbon brushes which ride on the commutator. The shunt is connected across the field supply and the series turns are connected in series with the armature. Characteristics of dc series motor studyelectrical. The compound motor is a motor which has both shunt and series field. Dc power input is converted into mechanical power at the shaft motor. Cumulative compound motor is capable of developing large amount of torque at low speeds just like series motor.
The principal advantage of a dc motor over ac motor is that its speed can be changed over a wide range by a variety of simple methods. Characteristics of dc motors through equations eeebooks4u. A universal motor is a special type of motor which is designed to run on either dc or single phase ac supply. In a compound dc motor, the series field flux and shunt field flux may oppose each other or may support each other depending on the relative connection between these two fields. These characteristics enable the operator to perform a wide variety of tasks. The principle of operation of a dc generator is similar to that of the ac generator, which was discussed previously. In the cumulative compound motor, the field produced by the series winding. A good material for the poles of a pmdc motor should have the apposite of the above. A rotating armature coil passes through a magnetic field that develops between the north and. Regardless of their complexity, they will control the components of the motor as illustrated in fig. Dc compound motors are desirable for a variety of applications because it combines the characteristics of a serieswound motor and a shuntwound motor. Each type has unique operating characteristics and applications. For each of them, there are different methods of speed control.
Dec 10, 2016 dc compound motor dc compound motor is the combination of series motor and shunt motor it has a series field winding that is connected in series with the armature and shunt field winding that is in parallel with the armature the combination of series and shunt winding allow motor to have a torque characteristics of the series motor. Characteristic of dc generators separately excited self excited and compound generator characteristic is the graph between the two dependent quantities. All the characteristics of the compound motor are the combination of the shunt and series characteristics. Characteristic of cumulative compound motor my tech info. This excessive current would operate the overload device, disconnect the motor from the supply, and thus protect the motor. In small dc motors, permanent magnets can be used for the stator. Important characteristics of electric motors are the starting to rated current and torque ratios. Types of dc motors include straightseries motors, splitseries motors, shunt motors, compound motors seriesshunt fields, and permanentmagnet pm motors.
Due to the advancements made in permanentmagnet materials, pm dc motors are one of the most widely used prime movers in industry today. Jul 11, 2019 in a series wound dc motor, the speed varies with load. Dc motors although ac motors are used in most of the cases, dc motors have many applications and used for multipurpose applications. In cumulative compound motor the flux produced by both the windings is in the same direction, i. The compound excitation characteristic in a dc motor can be obtained by combining the operational characteristic of both the shunt and series excited dc motor. From the above data, plot the external characteristics for a compound generator. Dc series motors are used where high starting torque required. In both the cases the external characteristic of the generator will be nearly same. The dc motor is a type of machine that transitions the form of input electrical energy to output mechanical energy. Mar 23, 2019 a compound wound dc motor also known as a dc compound motor is a type of selfexcited motor, and is made up of both series the field coils s1 s2 and shunt field coils f1 f2 connected to the armature winding as shown in the figure below.
Controls can range from handcranked rheostats to electronic circuitry. Find the efficiency of dc compound motor long shunt, 25h. A compound wound dc motor also known as a dc compound motor is a type of selfexcited motor, and is made up of both series the field coils s 1 s 2 and shunt field coils f 1 f 2 connected to the armature winding as shown in the figure below. The connection diagram of the compound motor is shown below. A cumulative compound can develop high starting torque at low speed like a series motor. Dc compound motor dc compound motor is the combination of series motor and shunt motor it has a series field winding that is connected in series with the armature and shunt field winding that is in parallel with the armature the combination of series and shunt winding allow motor to have a torque characteristics of the series motor. Characteristic of dc compound motor the compound motor is a motor which has both shunt and series field. Jun 12, 2019 the compound motor is a motor which has both shunt and series field. Whenever the shunt motor load is increased e b vi a r a and flux reduces as a result drop in the armature resistance and armature reaction. And there are two different types of compound motors in.
According to characteristics of dc motor, motors are used in the application. Both the field coils provide for the required amount of magnetic flux, that links with the armature. In this video we have explained different types of dc motor and their. Briefly, we can say that dc compound motor is a combination of both a shunt wound dc motor and series wound dc motor which means that compound motor has the advantage of high starting torque and efficient speed regulation so it can be used in industrial applications include. If applied voltage v is kept constant, the field current will remain constant, hence. Its operation is based on the principle that when a current carrying conductor is placed in a. A compoundwound motor has both a series and a shunt field winding, i. A dc motor having both shunt and series field windings is called a compound motor. Dc motor is an electromagnetic device which converts electrical energy into mechanical energy. Load characteristics of dc compound generator with differential and cumulative connection. There are both series and shunt fields separately excited fields. It is outer cover of dc motor also called as frame.
Open circuit and load characteristics of dc shunt generatorcritical resistance and critical speed. It shows the steady state characteristic of dc generators. The graph shows the torquespeed characteristics of a shunt dc motor. Perkins, in reference data for engineers ninth edition, 2002. I discuss the terminal characteristics of a differentially compound dc motor word press article summary. Characteristic of the compound motor is the combination of both series dc and shunt dc motor. Compound motor characteristics basically depend on the fact whether the motor is cumulatively compound or differential compound. Dec 22, 2017 i discuss the terminal characteristics of a differentially compound dc motor word press article summary. The selfexcited motors are further classified as shunt wound or shunt motor, series wound or series motor and compound wound or compound motor. Characteristic of dc generators separately excited self. In this post, we will look into the characteristics of a dc series motor. Characteristic of dc compound wound generators electrical. The dc differential compound motor is useful for constant speed application. Reverse the series field connection and repeat the previous steps.
Cumulative compound motor combines the operating characteristics of the series and shunt motors. Also we conclude that the motor is not permitted from running away at noload due to the presence of shunt field and due to the occurrence of series field winding the initial torque is increased. Speed torque characteristics of dc compound motor eeeguide. Hence the armature current differs and the speed of a dc shunt motor will continue constant which is shown in the fig dotted line ab. And operation wise this is its main difference from a shunt wound dc motor. When current carrying conductor is placed in a magnetic field it experience a force. Generally, three characteristic curves are considered important for dc motors which are, i torque vs. Speed control for a compound dc motor electric equipment. Characteristic of dc compound wound generators in compound wound dc generators both the field windings are combined series and shunt. The high torque capability of the series wound dc motor is somewhat. Types of dc motor a direct current motor, dc is named according to the connection of the field winding with the armature.
In a compound motor, if series and shunt windings are connected such that series flux is in direction as that of the shunt flux then the motor is said to be cumulatively compounded. All the characteristics of the compound motor are the combination of the shunt and series characteristic. A dc series motor is one type of dc motor in which field winding is connected in series with the armature winding. Speed control of dc motor shunt, series and compound. A compound dc motor connects the armature and fields windings in a shunt and a series combination to give it characteristics of both a shunt and a series dc motor. Characteristics of dc compound motor dc compound motors have both series as well as shunt winding. The characteristics of a shunt motor reveal that it is an approximately constant speed motor. Aug 11, 2018 there of many types of dc motors, each types has a special property which decide its compatibility for different application. There of many types of dc motors, each types has a special property which decide its compatibility for different application.
This provides a motor with a combination of the shunt and series characteristics. Power low in dc motor copper loss in armature, field and series windings brush loss is sometimes included v brushi a equivalent circuit of series motor 2. To understand how the series and shunt field fluxes interact to produce the various compound generator terminal voltage vs. Characteristics of dc shunt motor, dc series motor, dc. In a differential compound motor, the motor speed will increase with an increase in the load, which leads to an unstable operation. The most important part of any machine is its characteristics. The motors nameplate shows the base speed of the motor. Dc motors although ac motors are used in most of the cases, dc motors. With the above seen three characteristic we understood that cumulative compound has characteristics inbetween the shunt and series motor.
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