Brake test on dc shunt motor pdf file

When a shunt dc motor reaches its full speed, the armature current is directly related to the motor load. The shunt field windings of a dc shunt motor are made of smaller gauge wire, but they have many more turns than a serieswound dc motor. Lathes, drills, boring mills, shapers, spinning, and weaving machines series motor. The armature current can be written as tb a a v e i r where r a is armature resistance, p zn e b 60a i armature current is proportional to back emf. As you know that the construction of any type of dc motor is very similar to a dc generator. The dc brush motor also has two types of windings the excitation or field winding and the armature. Third is the serieswound dc motor and fourth is the compoundwound brushed dc motor which is a combination of both the shunt and series wound brushed dc motors. The dc shunt motor is 120vdc with rated speed of 1800 revolutions per minute. This is also well known that the dc machines can be used as a generator as well as as a motor, their is the difference of operation in both case i.

Electrical machines 1 pdf notes em 1 pdf notes smartzworld. Brake test on dc shunt motor electric motor electrical. Title of the experiment page no 7 retardation test on dc shunt motor. Brake test is also a method of finding efficiency of dc motors. 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. In this method, a brake is applied to a watercooled pulley mounted on the motor shaft as shown in fig. Depending on the motors design a tachometer system should be included. Load test on dc shunt motor and to find efficiency precautions. Your browser does not currently recognize any of the video formats available. Scribd is the worlds largest social reading and publishing site. Brake test on dc shunt motor free download as word doc. Determination of performance curves 10 separation of losses in dc shunt motor 11 speed control of dc shunt motor by field and armature control 12 retardation test on dc shunt machine. The purpose of this load test is to test which is used to test the performance. Click here to visit our frequently asked questions about html5.

The motor now works as a generator, producing the braking torque. Electrical machines for mechatronics laboratory 6 4 altering the armature voltage procedure using the lab equipments shown in figure 6. The torque speed characteristics separate by excited shunt of the machine under dynamic braking mode is as shown in fig. Methods of testing direct, indirect and regenerative testing brake test swinburnes test hopkinsons test fields test retardation test separation of stray losses in a d. 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. Set the inserted field resistance and the inserted armature resistance to their maximum values. This commutator and brush connection always keep the direction of the current and the direction of the magnetic field consistent. It is supplied with one ms powder coated electrical panel fitted with high insulation bakelite sheet. To determine the efficiency of the given dc shunt motor by conducting load test. 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. To obtain the performance characteristics of a dc shunt motor by load test. This paper discusses the speed and torque control of a shunt dc motor through matlab simulink simulations. As in any electric motor, the dc brush motor consists of the stator fixed part and the rotor movable part. The servo brake and drive system motor test bench may only be placed into service with an additional.

Electrical machinel dc laboratory manual grietelectrical and. Analog ammeter and voltmeter are provided on the front panel sheet. Once the motor reaches its full speed, it remains constant. Measurement of efficiency of shunt and series motors. The armature terminals or supply polarity of a separately excited dc motor or shunt dc motor when running are reversed. We believe that these faqs will be useful for your practical exams and interviews as well.

Dc motors were widely used in whole over the world. Speed control of electrical motors is an old but evergreen topic in industries. The characteristics of a shunt motor reveal that it is an approximately constant speed motor. This paper shows measurement of efficiency of dc shunt and series motor. Field rheostat should be kept in the minimum position. The connection diagram for dc shunt machine is shown in the figure below. Since load is very small in a shunt motor, armature current is also very low. The high number of turns allows a strong magnetic field to be generated, but the smaller gauge wires provide a high resistance and limit the current flowing through the shunt coil. 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.

Though there are separate branches for the flow of armature current and field current. What is dynamic braking or rheostatic braking of dc motor. When the motor speed is low, the braking torque becomes low and the motor attains to stop because of friction. Speed control of dc shunt motor with field and armature. This can be proudly known as workhorse of industrial systems. No load test on dc shunt generator 1 connect the circuit as shown in figure 1 with switches s1 and s2 open. Types of dc servo motors include series motors, shunt control motor, split series motor, and permanent magnet shunt motor. A dc servo motor is an assembly of four major components, namely a dc motor, a position sensing device, a. Therefore, the supply voltage v and the induced voltage e b i. The positive torque corresponds to the motoring operation. Since they are connected in parallel, the armature and field windings are exposed to the same supply voltage. For a dc generator the output power is wasted in resistor. Speed control method of dc series motor shubham sharma, simran singh oberoi, siddharth nair. Dc shunt motor should be started and stopped under no load condition.

However in the ground fault mode, the current flows from the ac line input, through the. Therefore, a shunt resistor in the ground path can detect these overcurrent conditions. The first type, is the permanent magnet brush dc motor. The principle of the dc motor relies on the concept of commutation. A 240v dc shunt dc motor has an armature resistance of 0. Swinburnes test and speed control of dc shunt motor. The motor speed reduces once the value of resistance r decreases, and then the breaking torque might be controlled at a large value.

Speed control of dc shunt motor with field and armature rheostat control 79 2. If spring balances are calibrated in kilograms, the motor output is given by, motor output. In this paper discussed about load test of dc series and shunt motor. To verify kirchhoffs voltage and current law in a passive resistive network. One end of the rope is fixed to the floor via a spring balance s and a known mass is suspended at the other. Electrical and electronics engineering lab manual pdf. A shunt dc motor connects the armature and field windings in parallel or shunt with a common d. In a shunt motor, the field and armature windings are connected in parallel. The seven dc drive models of the library, designated dc1 to dc7, are based on the dc brush motor in the electric drives library.

To draw the open circuit characteristics curve of dc shunt generator. 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. What you need is a variable dc power supply for this you need to know the ratings of the motor. Geethanjali college of engineering and technology department electrical and electronics engineering list of experiments s. Load test on dc shunt motor, dc shunt wound motor, direct.

So back emf is a controlling factor of armature current. To obtain the performance characteristics of dc shunt motor by direct loading. The dc brakes are operated by a solenoid similar in that is being driven by the momentum of the armature design to the ac solenoid brake fig. Equivalent circuit parameters are armature resistance ra 110 ohms, field resistance rf 2. To draw the performance characteristics of the given dc shunt motor by conducting load test.