Dc starter face plate type suitable for above motor. Pdf this paper discusses the speed and torque control of a shunt dc motor through matlab simulink simulations. Torque control of a shunt wound and dc motor of an electric vehicle by means of continuous field control and stepwise adjustment of the armature voltage. 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. As the rotating speed of dc shunt motor depends on armature voltage and field current applied to the shunt motor, therefore, these two process parameters were varied during. Analog ammeter and voltmeter are provided on the front panel sheet. Torque control of a shunt wound and dc motor of an electric vehicle by means of. In this post we had collected some of the most frequently asked electrical machines 1 viva questions with detailed answers. Circuit diagram load test on dc shunt motor figure 1. It is a machine which converts electrical energy into mechanical energy.
Practice dismantling and assembling in dc shunt motor. A shuntwound motor has decreasing torque as speed increases. Speed control of dc shunt motor by armature and field control. Speed control of dc shunt motor so by varying one of these parameters, it is possible to change the speed of dc shunt motor. In a shunt dc motor, the armature and field windings are connected in parallel. These motors are offered in cface models for mounting to our enclosed gear drives, and they are available in 16 20 hp and cover voltage ranges from 115 vac to 460 vac. Torque control of a shunt wound and dc motor of an electric vehicle by means of continuous field control and stepwise adjustment of the armature voltage citation for published version apa. Depending on the parameter being controlled, methods of speed control of shunt dc motor are classified as follows. A shunt dc motor connects the armature and field windings in parallel or shunt with a common d. In dc series motor the field windings are connected to the armature in series so that whole current flows. Continuous currents should not exceed 80% of the shunt rating. State two ways by which the output polarity of a separatelyexcited dc shunt generator can be changed 2. Electrical machinel dc laboratory manual grietelectrical and. Shunt dc motors electrical calculations and induction motor.
Dc shunt motor but field rheostat control method is most reliable, economic and independent of load on the motor. However, short term currents that occur in motorstarting or enginecranking can exceed the shunt rating by a factor of 2 or more without damage to the shunt or meter. A shunt wound motor has decreasing torque as speed increases. Practical book, test and assignment book, instructor guide, audio visual aid wall charts and. 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. Jun 25, 2015 electrical machines 1 viva questions and answers in this post we had collected some of the most frequently asked electrical machines 1 viva questions with detailed answers. Once the motor reaches its full speed, it remains constant. In this method, a brake is applied to a watercooled pulley mounted on the motor shaft as shown in fig. Before discussing the speed control of dc shunt motor, we have to find the factors affecting the speed of a dc motor. To obtain the performance characteristics of a dc shunt motor by load test. When a shunt dc motor reaches its full speed, the armature current is directly related to the motor load. To conduct a load test on dc shunt motor and to find its efficiency. Dc motors calculating efficiency all about circuits. Jan 14, 2018 load test on dc shunt motor and to find efficiency precautions.
To control the speed of dc shunt motor using field control method. A 240v dc shunt dc motor has an armature resistance of 0. A shuntwound motor is a dc motor in which the wound electromagnetic rotor field is in parallel not series with the armature. Speed control, armature, rpm field control, dc motor, series, parallel, voltage, and current i.
Speed control methods of dc shunt motor my tech info. Dc shunt motor should be started and stopped under no load condition. Speed control of dc shunt motor your electrical guide. Dc motor principle a machine that converts dc power into mechanical energy is known as dc motor. Theory the back emf for a dc motor is given by, p nz back emf, e b 60 a the number of poles, p the armature conductors, z and the number of parallel paths, a are constant for a particular machine. Q what happens if dc supply is applied to the transformer. Parts and principle of operation of a shunt dc motor.
However, the voltage differential increases and causes an increase of input current to the motor. Armature rheostat should be kept in the maximum resistance position at the time of starting and stopping the motor. Lathes, drills, boring mills, shapers, spinning, and weaving machines series motor. This motor is used when both a high starting torque and good speed regulation is needed. Boston gear offers a wide range of odp open drip proof ac motors, including brake motors.
In this method, an increase in controlling resistance reduces the field current with a consequent reduction in flux and. Field rheostat control of dc shunt motor in this method. Speed variation is accomplished by means of a variable resistance inserted in series with the shunt. Dc shunt motor theory quiz questions electrician practice tests. Dc motors plays an important role in energy conversion process. At noload, the motor draws 3a from the 200v supply and and runs at 1500 rmin. On occasion, a field regulator is contained within the field circuit of dc shunt motor for additional speed adjustment. Test the shunt field continuity by measuring and recording the resistance of the shunt with an ohmmeter. One end of the rope is fixed to the floor via a spring balance s and a known mass is suspended at the other. In this post, we will discuss about various speed control methods of dc shunt motor. 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.
Speed control of dc shunt motor with field and armature. In a field loss event, why does a shunt wound dc motor run away. The principle of the dc motor relies on the concept of commutation. We believe that these faqs will be useful for your practical exams and interviews as well. In mechanical system, speed varies with number of task so speed control is necessary to do mechanical work in a proper way. Dc shunt motor speed control armature control method. The machine used in this experiment is a representative of an industrial dc motor or generator with a rated power of tens of kilowatts. 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. As we know that if we increase load the armature speed will decrease so that back emf also decrease or say armature current will increase and we know that torque depends on armature current ia in a dc shunt motor so the flux could be constant torque proportional to flux. The shunt winding has a large number of turns so that it has appreciable inductance.
Armature resistance control and field flux control the dc motor converts the mechanical power into dc electrical power. This type of motor has good speed regulation even as the load varies, but does not have the starting torque of a series dc motor. Hopkinsons test is another useful method of testing the efficiency of a dc machine. 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. This method is only applicable when we want speed which is higher than the normal speed of the motor. Title of the experiment page no 7 retardation test on dc shunt motor. Though there are separate branches for the flow of armature current and field current. Torque control of a shunt wound and dc motor of an. By means of this method, the motor can be worked at any speed up to its maximum speed. Load test on dc shunt motor and to find efficiency precautions. An efficient method for speed control of dc shunt motor. Aug 03, 2018 hopkinsons test is another useful method of testing the efficiency of a dc machine. Since the shunt field coil is made of fine wire, it cannot produce the large current for starting like the. No load test on dc shunt generator 1 connect the circuit as shown in figure 1 with switches s1 and s2 open.
To find the various parameters such as torque, input power, output power etc. To conduct load test on dc motor with shunt excitation and plot the typical characteristics. Load test on dc shunt motor offered by unicon instruments, a leading supplier of dc shunt motor in sadar bazar, ambala, haryana. Relation between torque and speed in a dc motorsay dc. May 24, 2015 a 10 hp 240 v dc shunt motor draws 38a of line current the field resistance is 170 ohms and the armature resistance is 0 4 ohms the rotational losses which include the brush contact loss are 100 w and the core losses are 5% of rated shaft output power d. Reduced field strength will cause high armature currents. A shunt wound motor is a dc motor in which the wound electromagnetic rotor field is in parallel not series with the armature. To determine the efficiency of the given dc shunt motor by conducting load test. If a dc generator delivers 180 w to a load, what is.
Experiment 6 shunt dc motor ii objective to study the behavior of a shunt dc motor speed when the field resistance is altered. Since load is very small in a shunt motor, armature current is also very low. To study the behavior of a shunt dc motor speed when the armature voltage is altered. To control the speed of dc shunt motor using armature control method. To control the speed of a dc shunt motor by the method of a. It is a full load test and it requires two identical machines which are coupled to each other. Consequently, shunt motor will not usually run on a. Noload speed of which of the following motor will be highest. Thus the speed of dc motor is given by, eb v i a r a. Speed of a shunt dc motor can be easily controlled.
Speed control method of dc series motor shubham sharma, simran singh oberoi, siddharth nair ece dept, dronacharya college of engg abstract. A shunt motor has slightly different operating characteristics than a series motor. Notice the shunt coil is identified as a coil of fine wire with many turns that is connected in parallel shunt with the armature. Dc motors although ac motors are used in most of the cases, dc motors have many applications and used for multipurpose applications. Since they are connected in parallel, the armature and field windings are exposed to the same supply voltage. It is supplied with one ms powder coated electrical panel fitted with high insulation bakelite sheet. The field winding is connected in parallel with the armature. One of the most important features of the dc motor is that their speed can easily be control according to the requirement by using simple methods. Laboratory manual electrical machines and applications. Jul 11, 2019 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. A dc motor must have 100% field strength to produce its maximum torque and to keep the armature amperage within proper limits. The voltage applied to the motor may be reversed by backing the field current of generator through controller fc.
From my understand of electric motor, the armature spins because its magnetic field pushespulls against the field windings magnetic field. To perform open circuit test and short circuit test on a. One of these two machines is operated as a generator to supply the mechanical power to the motor. Relation between torque and speed in a dc motor say dc shunt. This paper discusses the speed and torque control of a shunt dc motor through matlab simulink simulations. In this paper will be studying about the various speed control methods of a dc series motor. Field loss in a shunt wound dc motor physics forums. This type of winding is called shunt winding and the motor shunt dc motor. Load test on dc shunt motor unicon instruments exporter. Shunt motor is a special type of dc motor which runs at. If a dc generator delivers 180 w to a load, what is the minimum mechanical power in watts. A 10 hp, 200v dc shunt motor has an armature resistance of 1 ohm and shunt field resistance of 100 ohms. Calculate the rotational losses under this operating condition. In electrical terminology, a parallel connection is termed shunt.
The company was incorporated in 1954 and is registered with indiamart. A stab is shaped piece of metal that makes up a certain type of wound rotor. I have a doubt on relation between torque and speed in a dc motor. If i remove power to the field winding, then shouldnt the motor slows down because the.
Load test on dc shunt motor to draw speed torque and horse power efficiency characteristics. The aim of this this paper is to describe the principle of. Therefore the voltage drops i a r a will be negligible as compared to the external supply voltage v. Dec 25, 2017 in this video you will learn about speed control of dc shunt motor now you can join our whatsapp group. A good material for the poles of a pmdc motor should have the apposite of the above. Ia sience flux constant torque proportional to ia so when armature. Introduction dc series motor a dc motor, whose field winding is excited by the current produced by itself, is called selfexcited. One of these two machines is operated as a generator to supply the mechanical power to the motor and the other is operated as a motor to drive the generator. To draw the performance characteristics of the given dc shunt motor by conducting load test. 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. The characteristics of a shunt motor reveal that it is an approximately constant speed motor. C is applied to a shunt motor, the large inductive reactance of shunt winding will reduce the field current too much.
The dc shunt motor is 120vdc with rated speed of 1800 revolutions per minute. Field rheostat should be kept in the minimum resistance position at the time of starting and stopping the motor. Its operation is based on the principle that when a current carrying conductor is placed in a. To study the behavior of a shunt dc motor speed when a. What is the difference between a dc shunt and a series motor. A dc motor draws more current with a mechanical load applied to its shaft because the cemf is reduced with the speed. The dc generator as we know can be either separately excited or self excited in shunt. This commutator and brush connection always keep the direction of the current and the direction of the magnetic field consistent. Field rheostat should be kept in the minimum position.
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