Keep in mind, however, that they cannot produce high starting torque, so the load at startup must be small. Load test on singlephase transformer and three phase transformers. To obtain the characteristics of speed control by the above mentioned methods. Let us first understand how it generates variable dc. Horizontal split casing pumps 3d installation manual duration.
Speed control of dc shunt motor your electrical guide. The speed is inversely proportional to flux it is directly proportional to armature voltage drop i a r a. Before the magnetic saturation, the field flux is directly proportional to the field current. Explain two advantages of the electric drive system of the electric motors. 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. Experiment 5 dc motor speed control it is prefered that students answer the questions before doing the lab because that provides the background information needed for this lab.
For a dc shunt motor field winding is connected in series with the armature and current passing through the series winding is same as the armature current therefore the series field winding has fewer turns of thick wire than the shunt field winding. Open circuit and short circuit tests on single phase transformer. As supply voltage is constant the i sh can only varied by inserting extra resistance in the field circuit. Conclusion in this lab experiment the dc motor speed control. The voltage applied to the motor may be reversed by backing the field current of generator through controller fc. 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. This is different to speed regulation where the speed is trying to be maintained or regulated against the natural change in speed due to a change in the load on the shaft. This paper discusses the speed and torque control of a shunt dc motor through matlab simulink simulations. The field current can be changed by changing the rheostat r connected in series with the field. As resistance increased, the value of the field current will reduce. Adjust the armature voltage to values shown in table 1.
It simply chops fixed dc and generates variable dc. At present, variable voltage is achieved by scr controlled ac to dc converter unit is used to. In many different applications it is required to control speed of dc motor. C shunt motor as a function of armature voltage, field current, and external resistance in the armature circuit. You can sense the effect of speed control of dc motor in the movement of robotic vehicles, movement in elevators, movement in paper mils and so on when different types of dc motors. Speed control of dc shunt motor with field and armature. The field of the shunt motor is supplied from a constantvoltage exciter e. Armature resistance control and field flux control the dc motor converts the mechanical power into dc electrical power.
Variations of speed with armature voltage control at constant field current. Speed control of dc shunt motor objective to study the speed control of a dc shunt motor by the following methods. Load characteristics of dc shunt and compound motor. Load test on singlephase transformer and three phase transformer connections. By decreasing the flux, the speed can be increased and vice versa. Short circuit protection protects control from a short circuit at motor connections. From the above speed relations, the speed of a dc motor can be varied by changing the applied voltage to the armature i flux. The flux of a dc motor can be changed by changing ish with help of a shunt field.
Speed control methods of dc shunt motor my tech info. Speed control of a dc motor is either done manually by the operator or by means of an automatic control device. Since they are connected in parallel, the armature and field windings are exposed to the same supply voltage. Variation of speed with variation of field current at constant voltage.
Speed control of dc shunt motor electric motor direct current. By means of this method, the motor can be worked at any speed up to its maximum speed. On occasion, a field regulator is contained within the field circuit of dc shunt motor for additional speed adjustment. Load test on dc shunt motor offered by unicon instruments, a leading supplier of dc shunt motor in sadar bazar, ambala, haryana. Speed control of dc shunt motor with field and armature rheostat control 79 2. To control the speed of dc shunt motor using field control method. In order to change the speed, we have to change flux.
Connect the motor as a shunt motor connect the field terminals in parallel with the armature terminals and drive the motor from a single power supply. To control the speed of dc shunt motor by armature control method and field control method apparatus requirred. Speed control of dc shunt motor and 3ph induction motor. We can control the shunt field current by inserting a rheostat in the field circuit. Active bridge limits the ac line inrush current when power is turned on and also prevents high speed runaway if the power transistor shorts. In the past, wardleonard method is used for voltage control method. Speed control methods of dc motor speed control of shunt motor 1. This can be achieved by changing the field current. From the expression of the speed of a dc motor, we have seen that the speed of the motor is inversely proportional to its field flux. In this lab experiment, the dc motor speed control was studied. Experiment 5 dc motor speed control walter scott, jr. The different methods of speed control in dc shunt motors are 1.
Load test on dc shunt motor unicon instruments exporter. Electrical machinel dc laboratory manual grietelectrical and. Swinburnes test and speed control of dc shunt motor. Dc motor speed control using chopper engineersgarage. Controlling the speed of dc motor can be done by different ways like using a potentiometer and also by a controlled current to the armature. A flux control method of dc shunt motor the flux of dc motor is a function of field current i sh. Speed control of dc shunt motor free download as pdf file. Speed control of dc motor experiment 3 speed control of dc motor objectives to study a sample firing circuit of scr, and understand the characteristics of scr, to measure the dc motor constants, to study the speed control of a dc motor in open loop mode using the laboratory universal firing circuit and halfbridge scr rectifier. This decreases i sh and hence flux ecrease in flux increases speed. The motor shaft should start rotating in the desired direction. May 18, 2016 horizontal split casing pumps 3d installation manual duration.
What are the methods for controlling the speed of a dc shunt. Speed control of dc motor is the most important feature we interest in, when we control the speed we vary it according to the requirements and the operation we need. Bc354 pwm dc motor speed control installation and operating. Hence this method is used to increase the speed above rated speed. The company was incorporated in 1954 and is registered with indiamart. 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. Chopper is a device that gives variable dc output from applied fixed dc input. To obtain speed control of dc shunt motor using a armature resistance control b field control. To obtain speedtorque characteristics of a dc shunt motor. Speed control of dc shunt motor by armature and field control. From this expression we can obtain the dc shunt motor speed control methods. Apparatus type range quantity 1 voltmeter mc 0300v 1 2 ammeter mc 020a 1 3 rheostat 1250. Dc motor shunt field 5 6 8821 120 volt source dc 8 8 n 8821 0120 volt source dc voltage variable 7 7 n figure 1. The different methods of speed control of dc shunt motor are flux control method, armature control method and voltage control method.
Speed control of dc motor full guide for controlling the. 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. 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. The dc shunt motor is 120vdc with rated speed of 1800 revolutions per minute. Apart from these techniques, pulse width modulation is the effective way to implement motor speed control. The field of the generator g is also supplied from the exciter e. One of the popular methods of speed control of dc motor is using chopper. The term project develops a speed control system for a direct current dc motor.
Separately excited connection diagram turn on the power supply. The set up for speed control of dc shunt motor using flux control technique is shown in the figure. The armature of the shunt motor m whose speed is to be controlled is connected directly to a d. K e b o where, kconstant this shows the speed of a dc motor is directly proportional to the back emf and inversely proportional to the flux per pole. In this post, we will discuss about various speed control methods of dc shunt motor. This lab allowed us to further investigate the characteristics of the various dc motor speed control schemes. To control the speed of dc shunt motor using armature control method. Load test on dc shunt motor to draw speed torque and horse power efficiency characteristics. Jan 29, 2017 this video teach you to understand the speed control method of dc shunt motor with practical demonstration.