Brake test on dc shunt motor experiment pdf

In dc machines this test is applicable only throughout the flux is constant at all load dc shunt machine and dc compound machine. The motor now works as a generator, producing the braking torque. Test result of boosted voltage while running motor at 2500 rpm. Three very popular devices used to make things move include dc motors, rc servos, and stepper motors. To conduct load test on dc shunt generator and to draw its external and internal characteristics 2.

To determine the efficiency of the given dc shunt motor by conducting load test. S1 power switch to switch on sw1 speed switch and starter switch for armature sw2 speed switch for field winding r1 to r9 wirewound high power resistors for the starting of the motor sw2 must be on position 0. Retardation test is also called as running down test. The open circuit characteristics for a dc generator are determined as follows. Assuming stator flux to be linear function of field current, determine the constant kk f. This parallel configuration allows independent path of current for field winding and armature. The simple brake test described above can be used for small motors only, because in the case of large motors, it. C of a dc shunt generator and to determine its critical.

In this technique, the dc generator or dc motor is run as a motor at no load. Swinburnes test is the simplest indirect method of testing dc machines. Construction and principle of operation of the shunt dc motor. Dc motor principle a machine that converts dc power into mechanical energy is known as dc motor. Continue the experiment till saturation of the field is reached. Eee lab manual pdf electrical electronics engineering2020. Ee 448 laboratory experiment 4 introduction to dc motors 4 assuming shunt connected dc motor, compute back emf, field resistance, armature resistance, field loss, armature loss, power efficiency, starting torque, and noload speed. Smooth braking of a motor can be achieved by electric braking.

Ee 448 laboratory experiment 4 introduction to dc motors 2 i. In the brake test compound motor we are mainly used in long shunt compound. The armature terminals or supply polarity of a separately excited dc motor or shunt dc motor when running are reversed. C shunt motor is conducted and its performance curves are drawn. Now in this article we are going to discuss about retardation test on dc machines.

To predetermine the efficiency of a dc shunt machine when running both as generator and motor. Swinburnes test and predetermination of efficiencies as generator and motor. Sno name of the experiment date signature 1 magnetization characteristics of dc shunt generator. Two common basic methods used for braking a motor are dc injection braking and dynamic braking. In other words, the motor is stopped by the voltage and current action in the circuit rather than the mechanical friction brakes on the rotor. Dc machines can be tested by three different methods namely direct method, indirect method and regenerative method.

The field current lf is obtained from an external independent dc source. You can do a simple experiment to distinguish between the coast and brake mode. This is very efficient way to find out stray losses in dc shunt motors. Circuit diagram load test on dc shunt motor figure. We came up with relatively simple and inexpensive solution that may be read more. Thus, this method is an economical and convenient method of testing of dc machines. Brake test is also a method of finding efficiency of dc motors.

Load test on singlephase transformer and three phase transformers. In electrical terms, parallel is generally denoted as shunt. We can run the machine as a motor or as a generator. This data at the end of the experiment can also be exported to the system. 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. Brake test on dc shunt motor electric motor electrical engineering. Brake test in one of the most simple way of finding efficiency of any kind of dc machine. We know that any moving or rotating object acquires kinetic energy. In this method, the dc machine generator or motor is run as a motor at noload and losses of the machine are determined. Speed control of dc shunt motor by field and armature control. Before starting the experiment maintain rheostat at maximum position. Speed control of dc shunt motor with field and armature.

As the constant loss is known the efficiency can be predetermined at any load. In this method, a brake is applied to a watercooled pulley mounted on the motor shaft as shown in fig. Geethanjali college of engineering and technology department electrical and electronics engineering list of experiments s. Electrical machines for mechatronics laboratory 7 4 speed control of series dc motors unlike with the shunt dc motor, there is only one efficient way to change the speed a series dc motor. Swinburnes test and speed control of dc shunt motor. That method is to change the terminal voltage of the motor. Determination of characteristics 3 brake test on dc shunt motor. Electrical and electronics engineering lab manual pdf eee.

Swinburnes test for dc machines in this technique, the dc generator or dc motor is run as a motor at no load. C shunt generator and to determine the critical field resistance and critical speed. 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. O from the above two characteristics of dc shunt motor, the torque developed and speed at various armature currents of dc shunt motor may be noted. Same voltage is applied to both shunt winding and armature in this motor. Applied voltage 200 v line current 30 a calculate the output power and the efficiency. Dc motors although ac motors are used in most of the cases, dc motors have many applications and used for multipurpose applications. Scribd is the worlds largest social reading and publishing site.

Dc injection braking is a method of braking in which direct current dc is applied to the stationary windings of an ac motor after the ac voltage is removed. Riosque y zack special edition hd recommended for you. The power required to test a large machine is small. Introduction to electrical power and machines eet2166. Apparatus range type quantity 1 ammeter 020a mc 1 2 voltmeter 0300v mc 1 3 rheostat 1250. Aug 22, 2018 it is also known as reverse current braking. Swinburnes test is the most commonly used and simplest method of testing of shunt and compound wound dc machines which have constant flux.

Fields test for series motor this test is applicable to two similar series motors. For real dependable measurement you might need special equipment such as an adjustable torque load it could be small particle brake coupled with the motor shaft and measuring tool such as dynamometer. 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 braking. Sep 18, 2019 to determine experimentally the magnetization or open circuit characteristic of a d. Brake test on dc shunt motor free download as word doc. Torque and efficiency calculation simple electric motors.

Washing machine motor wired in as series motor suicide motor duration. 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. Because loading will be applied directly on shaft of the motor by means of a belt and pulley arrangement. The brake test is the one kind of load test on dc shunt motor. Its operation is based on the principle that when a current carrying conductor is placed in a. Electrical and electronics engineering lab manual pdf. These experiments consolidates the students knowledge of construction,operation and performance of dc. The dc shuntwound motor, running on direct current, has its field windings placed in parallel to the armature. When the losses of dc machine wellknown, then we can find the efficiency of a dc machine in advance at any desired load. Therefore, the supply voltage v and the induced voltage e b i. Lab report of electrical machines for lab1 characteristics of dc shunt motor, lab 1.

In this article we are going to discuss about brake test on d. Electrical machinel dc laboratory manual grietelectrical and. Series motors which are mainly used for traction work are easily available in pairs. The brake band is fixed with the help of wooden blocks gripping the pulley. In the previous articles we have seen brake test, hopkinsons test which are essential to find out dc machine efficiency. What is dynamic braking or rheostatic braking of dc motor. Determination of critical field resistance critical speed. The brake is set when power is removed from the operating coil through stored energy from a torque spring that is compressed when the brake is electrically set.

In this test we get total stray losses nothing but combination of. Speed control of dc shunt motor with field and armature rheostat control 79 2. Heat produced due to friction between belt and brake drum is reduced by pouring. Pdf this paper discusses the speed and torque control of a shunt dc motor through matlab simulink simulations. To verify kirchhoffs voltage and current law in a passive resistive network. Jan 29, 2017 this video teach you to understand the speed control method of dc shunt motor with practical demonstration.

To draw the performance characteristics of the given dc shunt motor by. 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. Introduction the purpose of this experiment is to examine the construction of a dc motor generator, to learn the basic motor wiring connections, and to study the performance characteristics of a shunt and series dc motor. The following readings are obtained when doing a load test on a d. In order to carry out this test, we require two identical d. Two basic methods used for braking a motor dc injection. What is theory of brake test on dc shunt motor answers.

Brake test also called as direct loading test of testing the motor. Determination of critical field resistance and critical speed. This video describes the a load test on dc shunt motor with calculation. To draw the performance characteristics of the given dc shunt motor by conducting load test. So the load test could be performed in two ways ie, by direct loading by indirectly loading in case of direct loading the motor is provide. Open circuit and short circuit tests on single phase transformer. As resistance increased, the value of the field current will reduce. Regenerative braking of bldc motors by daniel torres, applications engineer. To obtain the performance characteristics of a dc shunt motor by load test. Regenerative or hopkinsons test on dc machines is useful to determine the efficiency which the power. For the braking operation in dynamic braking, the motor is connected in two ways.

Tests on 1phase transformer 12 load test on 1phase transformer. 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. Since they are connected in parallel, the armature and field windings are exposed to the same supply voltage. Take a brushed dc motor and try to spin the shaft with your fingers, leaving the leads floating. O if these values are plotted, the graph representing the variation of speed with torque developed is obtained. We will look at both in detail, starting with electric braking. To conduct load test on dc shunt motor and to find efficiency.

It is a direct method and consists of applying a brake to a. Once the losses of the machine are known, its efficiency at any desired load can be determined in advance. Generally, this test can be done for the low rated dc machines. The main advantages of the swinburnes test are as follows. One end of the rope is fixed to the floor via a spring balance s and a known mass is suspended at the other. It is often necessary in many applications to stop a running motor rather quickly. Electrical machines lab report 12 eet2166 mmu studocu. Batch mates should be able to explain the purpose of the experiment. This is an efficient and effective method of braking most ac motors. One machine runs normally as a motor and drives generator whose output is wasted in a variable load r fig. In the brake test compound motor we are mainly used in long shunt compound motor. 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.

Continue the experiment till full load of the motor is reached. D c shunt motor make conclusion sd control of dc shunt motor dc shunt motor experiment sd control of dc shunt motor. In case of dc shunt motors, armature is disconnected from the supply and a. State two ways by which the output polarity of a separatelyexcited dc shunt generator can be. That is the reason behind naming it a dc shunt motor. Maintain constant armature voltage through out the experiment. One end of the band is fixed to earth via a spring balance s. This is the complete theory of brake test on dc shunt motor including laboratory manual. Brake test on dc shunt motor electric motor electrical. In this test the efficiency of the machine at any load is predetermined. Spring balance reading 10 kg and 35 kg diameter of the drum 40 cm speed of the motor 950 r.