In this article we are going to discuss about brake test on d. Dc shunt motor theory quiz questions electrician practice tests. Since they are connected in parallel, the armature and field windings are exposed to the same supply voltage. Noload and blocked rotor test on an induction machine aim. At the time of starting check that the belt on the pulley is free, so that there is no. C of a dc shunt generator and to determine its critical.
In electrical terminology, a parallel connection is called shunt. Dynamic braking or rheostatic braking of dc motor in dynamic braking, a braking resistor rb is connected across the armature as soon as the dc motor is disconnected from the supply mains. Types of dc motors separately excited motor shunt excited motor series excited motor compound excited motor permanent magnet pm motor. Q what happens if dc supply is applied to the transformer. Pdf laboratory manual electrical machines ayyappa javangula. The main advantages of the swinburnes test are as follows. According to stephen and dale, 2009 the field coils of a series motor has a low resistance consisting of few turns of large diameter coils of wire while the field coils of the shunt motor has a high resistance made up of. As we know that if we increase load the armature speed will decrease so that back emf also. It is often necessary in many applications to stop a running motor rather quickly. Dc motors although ac motors are used in most of the cases, dc motors have many applications and used for multipurpose applications. For the braking operation in dynamic braking, the motor is connected in two ways.
Dc shunt motor speed control and analysis using ziegler nichols algorithm with pid controller yogesh sharma l,a shis patra 2 1, 2 electrical engineering department, m. 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. I have a doubt on relation between torque and speed in a dc motor. Electrical machinel dc laboratory manual grietelectrical and. In this post, we will discuss about various speed control methods of dc shunt motor. All motors have been sized for roughly the same mechanical power rating. Now close switch s1 and slowly increase the voltage supplied to 3phase induction motor using autotransformer until it rotates at the rated speed of dc machine.
The present research work deals with the application of response surface methodology rsm for controlling as well as estimating the rotating speed of a dc shunt motor. In this test the efficiency of the machine at any load is predetermined. A shunt connected dc motor has the following magne. As the constant loss is known the efficiency can be predetermined at any load. Load test on dc shunt motor to draw speed torque and horse power efficiency. In this paper discussed about load test of dc series and shunt motor. On occasion, a field regulator is contained within the field circuit of dc shunt motor for additional speed adjustment.
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. Speed control methods of dc shunt motor my tech info. An efficient method for speed control of dc shunt motor using. To study the behavior of a shunt dc motor speed when the armature voltage is altered. As the test is on noload, it is impossible to know whether commutation would be satisfactory at fullload and whether the temperature rise would be within the specified limits. In a shunt dc motor, the armature and field windings are connected in parallel. Jun 02, 2015 fields test for series motor this test is applicable to two similar series motors. Series motors which are mainly used for traction work are easily available in pairs. To draw the performance characteristics of the given dc shunt motor by conducting load test. The open circuit characteristics for a dc generator are determined as follows. While in the noload test we shall be exciting the armature independently the load test as the name suggests shall be carried out in shunt. The voltage applied to the motor may be reversed by backing the field current of generator through controller fc.
Swinburnes test is the most commonly used and simplest method of testing of shunt and compound wound dc machines which have constant flux. As resistance increased, the value of the field current will reduce. Theory the efficiency of the dc machine can be accurately determined by the regenerative method, normally known as hopkinsons test. Jun 25, 2015 electrical machines 1 viva questions and answers. To select the motor type, rightclick on the electric motor block, select variantoverride using and then the desired motor. This kind of winding is called shunt winding and the motor shunt dc motor creation and principle of operation of a shunt dc motor is same as any other dc motor. Equivalent circuit parameters are armature resistance ra 110 ohms, field resistance rf 2. When the losses of dc machine wellknown, then we can find the efficiency of a dc machine in advance at any desired load. Therefore, mechanical loss can be assumed to remain same from no load to full load. The shunt motor runs at a speed defined by the expressions. To perform the brake test on the given dc compound motor and to obtain the. The direction of rotation of a dc series motor can be changed by 3.
The physical implications of the equations regarding device behaviour, and the need for speed control, are easily understood. The open circuit characteristics for a dc generator are determined. In a shunt dc motor, the armature and field windings are linked in parallel. Riosque y zack special edition hd recommended for you.
Dc motors concepts dc motors 1 noload speed of which of. Relation between torque and speed in a dc motorsay dc shunt. The power required to test a large machine is small. View notes speedcontrolofdcshuntmotor from boston 6. In this paper, various speed control techniques for a dc shunt motor namely. The resistances of the armature and shunt field are 0. We can run the machine as a motor or as a generator. These terms relate to the type of connection of the field windings with respect to the armature circuit. It is designed to demonstrate the fundamental concepts and also facilitates easy learning about two similar machines are required to carry out hopkinsons test. Since they are connected in parallel, the armature.
One end of the rope is fixed to the floor via a spring balance s and a known mass is suspended at the other. This test overcomes the drawback of swinburnes test, which. Dc motors unlv department of electrical and computer. Mar 06, 2019 swinburnes test is the most commonly used and simplest method of testing of shunt and compound wound dc machines which have constant flux. A dc shunt motor 50hp, 250v is connected to a 230v supply and delivers power to a load drawing an armature current of 200a and running at a speed of 1200rpm, given ra0. What is dynamic braking or rheostatic braking of dc motor. Jun 02, 2015 brake test it is a direct method and consists of applying a brake to a watercooled pulley mounted on the motor shaft as shown in fig. Brake test on dc shunt motor electric motor electrical engineering. To conduct load test on dc shunt motor and to find efficiency. Such a situation may occur in practice when the mechanical load itself becomes active.
To study the behavior of a shunt dc motor speed when a. Hopkinsons test of dc machine premier engineering lab. Speedcontrolofdcshuntmotor page 1 experiment no 9 aim. The lab is equipped with dc seriesshunt motor, compound motor, universal motor.
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. Brake test on dc compound motor free download as word doc. Brake test on dc shunt motor electric motor electrical. One machine runs normally as a motor and drives generator whose output is wasted in a variable load r fig.
Theory the shunt motor has a specific no load speed subsequently it does not run away when load is thrown off. Brake test on dc compound motor electric motor electrical. Brake test also called as direct loading test of testing the motor. Load test on dc shunt motor offered by unicon instruments, a leading supplier of dc shunt motor in sadar bazar, ambala, haryana. Equivalent circuit of compound excited dc motor differential compound. Find the speed and torque the power developed when ivered by the motor is 3000 w and there are no rotational losses given the motor operating is normal operating range.
Come prepared to the lab with relevant theory about the experiment. A dc shunt motor also known as a shunt wound dc motor is a type of selfexcited dc motor where the field windings are shunted to or are connected in parallel to the armature winding of the motor. To obtain the performance characteristics of a dc shunt motor by load test. Circuit diagram load test on dc shunt motor figure 1. Engineering astra laboratory manual electrical machines1 theory. We know that any moving or rotating object acquires kinetic energy. Relation between torque and speed in a dc motorsay dc. Speed control of dc motor shunt type aim a to study the speed control of dc motor below the normal range by armature resistance control and to plot speed vs armature voltage, characteristic. Dc machines can be tested by three different methods namely direct method, indirect method and regenerative method. A compoundwound motor has both a series and a shunt field winding, i.
One end of the band is fixed to earth via a spring balance s. As such the efficiency, calculated by swinburnes test is comparatively higher than the actual one. Shunt motor with electrical and torque characteristics simulink. E b vi a r a here, eb back emf, in volts ia armature current, in amps ra armature resistance, in ohms v terminal voltage, in volts. We believe that these faqs will be useful for your practical exams and interviews as well. The dc shunt motor construction is the same as any type of dc motor. C shunt, ii separately excited and iii series motor widely used are given at the beginning. Fields test for series motor this test is applicable to two similar series motors. However, when the track has a downward gradient, component of. To study the behavior of a shunt dc motor speed when a series resistor is inserted in the armature circuit. This article discusses what is a dc shunt motor, construction, working principle, circuit diagram, characteristics, brake test, speed control, applications. Construction, circuit diagram, and its applications. Speed control of dc shunt motor with field and armature.
A shunt dc motor connects the armature and field windings in parallel or shunt with a common d. Shunt motor is a special type of dc motor which runs at a constant speed. This motor can be constructed with the basic parts like field windings stator, a commutator and an armature rotor the working principle of a dc shunt motor is, whenever a dc motor is turned on, then dc flows throughout stator as well as the rotor. Dc shunt motor theory quiz questions electrical practice tests. Because loading will be applied directly on shaft of the motor by means of a belt and pulley arrangement.
Test of dc shunt motor configuration psychology essay. Swinburnes test for dc machines in this technique, the dc generator or dc motor is run as a motor at no load. Shunt motor with electrical and torque characteristics. There are 3 main types of dc motor that are available. In a shunt motor, the field and armature windings are connected in parallel.
According to stephen and dale, 2009 the field coils of a series motor has a low resistance consisting of few turns of large diameter coils of wire while the field coils of the shunt motor has a high resistance made up of small diameter coils of wire with many turns. To find the various parameters such as torque, input power, output power etc. A good material for the poles of a pmdc motor should have the apposite of the above. Load test on dc shunt motor unicon instruments exporter. Dc shunt motor speed control and analysis using ziegler. One of the machines is operated as motor, driving the other machine as a generator. A dc motor is any of a class of rotary electrical motors that converts direct current electrical. Its operation is based on the principle that when a current carrying conductor is placed in a. Swinburnes test method for testing dc shunt motor for a d. Brake test is also a method of finding efficiency of dc motors.
Swinburnes test and speed control of dc shunt motor. May 30, 2017 it is an attempt to explain the experiment of load test on dc shunt motor in tamil by dr. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Noload and blocked rotor test on an induction machine aim to estimate magnetization and leakage impedance parameters of induction machine using noload and blocked rotor tests theory an induction machine in its equivalent circuit form is akin to a transformer with slip as an additional parameter. The motor now works as a generator, producing the braking torque. Schematic diagram for hopkinsons test on dc machine. The dc generator as we know can be either separately excited or self excited in shunt.
To determine the efficiency of the given dc shunt motor by conducting load test. Parts and principle of operation of a shunt dc motor. Which of the following application requires high starting torque. The dc shunt motor is 120vdc with rated speed of 1800. In this post we had collected some of the most frequently asked electrical machines 1 viva questions with detailed answers. Machine is running as a motor at a speed of n 1 rpm. Brake test on dc shunt motor free download as word doc. It is a direct method and consists of applying a brake to a water cooled pulley. To control the speed of dc shunt motor using armature control method.
What is a dc shunt motor and its advantage and disadvantage. The brake band is fixed with the help of wooden blocks gripping the pulley. Brake drum should be cooled with water when it is under load. A shunt connected dc motor has the following magnetization curve. An efficient method for speed control of dc shunt motor. Thus, this method is an economical and convenient method of testing of dc machines.
By means of this method, the motor can be worked at any speed up to its maximum speed. Experiment 6 shunt dc motor ii objective to study the behavior of a shunt dc motor speed when the field resistance is altered. To control the speed of dc shunt motor using field control method. A comparison of the torquespeed characteristics for five different motor types. Measurement of efficiency of shunt and series motors. Measure and notedown the circumference of brake drum by using cotton thread. Dc motor principle a machine that converts dc power into mechanical energy is known as dc motor.
Several paragraphs that explain the motivation of the. In electrical terminology, a parallel connection is termed shunt. In dc shunt motor the armature and field winding are connected in parallel across the supply voltage the resistance of the shunt winding. This type of winding is called shunt winding and the motor shunt dc motor. Scribd is the worlds largest social reading and publishing site. Blockedrotor test circle diagram electromagnetism opencircuit test. The company was incorporated in 1954 and is registered with indiamart. Noload speed of which of the following will be highest.
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