In cumulative compound motors the series field assists the shunt field. Brake test on dc compound motor electric motor electrical. In this method, a brake is applied to a watercooled pulley mounted on the motor shaft as shown in fig. Brake test on dc shunt motor electric motor electrical engineering. Our test facility is one of the most advanced in the world. Brake test of dc motor is carried out as shown in figure below. A dc series motor is one type of dc motor in which field winding is connected in series with the armature winding.
Load characteristics of dc compound generator with differential and cumulative connection. C motor is the one of common application for industrial. Brushed dc motor theory and operation chris joyce, shane skikne, evan simpson, james nee january 8, 2014 abstract this study looked into the e ect of changing the material within the rotor of an electric motor. Because in the case of large motor it is different to dissipate the large amount of heat generated at the brake. Scribd is the worlds largest social reading and publishing site. In electrical terms, parallel is generally denoted as shunt.
A direct current moto r, dc is named according to the connection of the field winding with the armature. Characteristics of dc series motor studyelectrical. Atomic structure, energy band diagram, compare silicon and germanium, hole current, intrinsic semiconductor extrinsic semiconductor, compare voltage amplifier power amplifier, compare audio amplifier tuned amplifier, compare transistor scr, compare transistor mosfet, compare holding current latching current. Experiment 7 series dc motor i objectives to determine the torquespeed characteristic curve. The brake band is fixed with the help of wooden blocks gripping the pulley. Same voltage is applied to both shunt winding and armature in this motor. The field current lf is obtained from an external independent dc source. Prior to teslas inventions, direct current motors were the presiding type of motor. A dc motor may be thought of as a series of electromagnets, radially spaced around a common shaft. A compound wound motor has both a series and a shunt field winding, i. To conduct the no load test on the dc shunt motor and determine its.
Load characteristics of dc shunt and compound motor. Generally, this test can be done for the low rated dc machines. The open circuit characteristics for a dc generator are determined as follows. Dec 21, 2017 81 videos play all dc machines complete course includes fundamentals, motors and generators electrical is easy mix play all mix electrical is easy youtube troubleshooting a motor starter. Aug 03, 2018 hopkinsons test is another useful method of testing the efficiency of a dc machine. Brake test also called as direct loading test of testing the motor. Speed control of dc shunt motor with field and armature rheostat control 79 2.
Series wound dc motor construction, principle, speed and torque. The dc motor contains a stator and a rotor, the latter being more commonly called an armature. One end of the band is fixed to earth via a spring balance s. Series wound dc motor as we said before that this type of dc motor is a selfexcited dc motor which converts electrical power into mechanical power based on electromechanical law, but in this motor, the field winding is connected in series to the armature winding. It is a full load test and it requires two identical machines which are coupled to each other. Several paragraphs that explain the motivation of the. Aug 22, 2018 types of braking in a dc motor august 22, 2018 february 24, 2012 by electrical4u hello electrical people, you already know about the different types of motors that are available today and in this article, i shall discuss about the various techniques used to stop a dc motor or to bring it to rest as we cut off the supply. The electric braking of a dc motor is of three types, i rheostatic or dynamic braking, ii plugging or reverse current braking and iii regenerative beaking. Dec 01, 2016 dc machines can be tested by three different methods namely direct method, indirect method and regenerative method. Volume 2 of 4 module 3 dc circuits this module introduces the rules associated with the reactive components of inductance and capacitance and how they affect dc circuits. Another simpled method of measuring motor output is by the use of poney brake one form of the diagram.
Connect the brake supply cable inserted into the motor terminal box according to the diagram on the inside of the box cover, while connecting the brake with the motor maintain all the necessary. This is an efficient and effective method of braking most ac motors. Dc motors designed for your application dc motor applications tecowestinghouse motor company dc motors are ideally suited to a multitude of industrial. The tension of rope can be adjusted with the help of swivels obviously. Working principle from the above circuit diagram, we can conclude that if we want to increase the speed of the shunt motor, we will vary the field resistance. The selfexcited motors are further classified as shunt wound or shunt motor, series wound or series motor and compound wound or.
In such motors when armature current increases the field flux increases. C motor field windings 25092011 by lemau 2 comments d. Advantages and disadvantages of dc shunt motor load. Its operation is based on the principle that when a current carrying conductor is placed in a. The main advantages of the swinburnes test are as follows. Swinburnes test and speed control of dc shunt motor.
This course consists of 11 interactive, online lessons that address ac and dc motor theory. Brake test on dc shunt motor electric motor electrical. To perform the brake test on the given dc compound motor and to. Download as docx, pdf, txt or read online from scribd. Brake test on dc shunt motor free download as word doc. In this post, we will look into the characteristics of a dc series motor. Direct method of testing of dc machine, also known as brake test if carried out for a dc motor will be discussed in this post. An ac motor works by applying alternating current to stator windings, which produce a rotating magnetic field. Write the necessary magnetic polarities n for north and s for south on the armatures electromagnet pole tips, in order to. Dc motor principle a machine that converts dc power into mechanical energy is known as dc motor. Introduction a series dc motor is a motor whose filed windings consists of a relatively few turns connected in series with the armature circuit. In a brushed dc motor, the coils on the rotor utilize the motors magnetic eld to create torque on the axle. Brake test is also a method of finding efficiency of dc motors. Construction and principle of operation of the shunt dc motor.
As the constant loss is known the efficiency can be predetermined at any load. Riosque y zack special edition hd recommended for you. Using belt tightening hand wheels h1 and h2, the load of motor is adjusted to its rated value. The brake test is the one kind of load test on dc shunt motor. In case of dc shunt motors, armature is disconnected from the supply and a rheostat variable resistor is connected across it. The performance of any motor can be judged from its characteristic curves known as motor characteristics. As such, the field windings and armature are connected in a parallel combination, and in electrical terminology a parallel combination is known as a shunt. The result is a high standard of quality control that reinforces our manufacturing excellence. It is a direct method and consists of applying a brake to a. The armature and its windings are located in the path of this magnetic field, and. Overview the acdc motor theory course was specifically developed for electricians and electronic technicians as well as for the multicraft training needs of process and manufacturing facilities.
Two basic methods used for braking a motor dc injection and dynamic photo credit. Characteristics of dc compound motor in dc compound motors both shunt field and series field will be acting simultaneously. That is the reason behind naming it a dc shunt motor. Dc motors although ac motors are used in most of the cases, dc motors have many applications and used for multipurpose applications. The power required to test a large machine is small.
In this article we are going to discuss about brake test on d. Make the connections as per the circuit give supply to the motor, by closing dpst switch start the motor with the help of 3 point starter. Dc motors applied for the momentarily deliver rated around three or more times from their torque. Open circuit and load characteristics of separately and self excited dc shunt generators. Advantages and disadvantages of dc shunt motor load answers. One of these two machines is operated as a generator to supply the mechanical power to the motor. One end of the rope is fixed to the floor via a spring balance s and a known mass is suspended at the other end. First, one is separately excited dc motor and selfexcited dc motor.
A dc injection brake system can be used as an alternative to a friction brake system. Brake test is used to determine the efficiency of comparatively. This parallel configuration allows independent path of current for field winding and armature. Module 2 basic dc theory this module describes the basic concepts of direct current dc electrical circuits and discusses the associated terminology. Speed control of dc shunt motor with field and armature. The stator contains one or more windings per pole, all of which are designed to carry direct current, th ereby setting up a magnetic field. Load characteristics of dc compound generator with differential and cumulativeconnections. As resistance increased, the value of the field current will reduce. Dc injection brakes only require a small module located with the other motor switchgear andor drivers, mounted in a remote and convenient location, whereas a friction brake must be mounted somewhere on the rotating system.
A belt around the air cooled pulley has its end attached to the spring balance s1 and s2. To find out how to reverse the direction of rotation of a series dc motor. To conduct load test on dc compound motor and to find its efficiency. Electrical machinel dc laboratory manual grietelectrical and. Objective identify the components of an ac motor and explain their function. Because the magnetic field rotates in this way, an ac motor does not need power or mechanical aid to be applied to the rotor. Aug 08, 2017 this video provides all the basic concept of electric braking and application of dc motor in detail i created this video with the youtube video editor.
The final stage of brake installation onto the motor is mounting the fan and inserting the brake supply cable into the motor terminal box, 8. The dc shuntwound motor, running on direct current, has its field windings placed in parallel to the armature. This particular motor is of the permanent magnet type, with wire windings only on the armature. What is a dc shunt motor and its advantage and disadvantage.
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