The determination of the efficiency of dc machine is important for the testing of dc machines. To determine the efficiency of the given dc compound motor by conducting load test. 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. To find out how to reverse the direction of rotation of a series dc motor. A compoundwound motor has both a series and a shunt field winding, i. Pdf brake test on dc compound motor kalyan pavan academia edu dc motor wikipedia the free encyclopedia electric force dc motor wikipedia universal motor wikipedia dc shunt motors where are they.
Multiple choice questions mcqs on dc motor electrical ride. If stabilized shunt or compound wound motors are to be used, the series field must be isolated and not connected. Hopkinson s test is another useful method of testing the efficiency of a dc machine. The selfexcited motors are further classified as shunt wound or shunt motor, series wound or series motor and compound wound or. One end of the rope is fixed to the floor via a spring balance s and a known mass. 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. When a direct current brake is to be connected to an alternating current source, rectifier circuits are. Load test on dc shunt motor to draw speed torque and horse power efficiency characteristics. Each type has unique operating characteristics and applications. Dc injection brakes only require a small module located with the other motor switchgear andor drivers, mounted in a remote and convenient location, whereas a friction brake must be mounted somewhere on the rotating system. As the constant loss is known the efficiency can be predetermined at any load.
Parameter menu path default new value f250 programprotectiondc brakingdc injection braking start frequency 0. What will happen when dc shunt motor is started with load. C machines, a brake is applied to a watercooled pulley mounted on the motor shaft as shown in fig. Dc compound motor or compound wound dc motor is also a selfexcited motor, but it is a compound of both series and shunt field coils connected to the armature winding, a series field winding connected in series with the armature and a shunt field winding connected in parallel to the armature.
Swinburnes test and speed control of dc shunt motor. A dc injection brake system can be used as an alternative to a friction brake system. Brake test on dc shunt motor free download as word doc. I think the trigger is a doublethrow switch that removes the line power and shorts the motor when the switch is released. Electrical machines i lab manual anurag college of engineering. The main advantages of the swinburnes test are as follows. The purpose of this experiment is to examine the construction of a dc motorgenerator, to learn the basic motor wiring connections, and to study the performance characteristics of a shunt and series dc motor. Dc motors designed for your application dc motor applications tecowestinghouse motor company dc motors are ideally suited to a multitude of industrial. Our test facility is one of the most advanced in the world.
What are all the tests conducted on dc generator and motor. Brake test on dc compound motor circuit diagram diagram. To find the various performance parameters such as torque, input power, output power. Introduction to dc motors 1 ee 448 lab experiment no. Measure and notedown the circumference of brake drum by using cotton thread. Types of dc motor a direct current motor, dc is named according to the connection of the field winding with the armature.
Pdf sd and torque control of a dc shunt motor dc shunt motor dc shunt motor ar in dc shunt motor the field winding and ar is connected parallel cur remains fairly constant. Eassistant professor ppg institute of technology, coimbatore. A compound wound dc motor also known as a dc compound motor is a type of selfexcited motor, and is made up of both series the field coils s 1 s 2 and shunt field coils f 1 f 2 connected to the armature winding as shown in the figure below. In your test you were reversing the motor, so your closed loop drive was probably using.
Motorsummary of stepper motorspermanent magnet dc motorlowinertia dc motorsshelltype lowintertia dc motorprintedcircuit disc dc motorpermanentmag. Contact the motor manufacturer for motor derating under these conditions. Two basic methods used for braking a motor dc injection and dynamic photo credit. To draw the performance characteristics of the given dc compound motor by conducting load test. Two basic methods used for braking a motor dc injection.
Thus, this method is an economical and convenient method of testing of dc machines. When the system falls below approximately 60 psi, the brakes are automatically locked by springs and the bus becomes immobile. For a standard brushed dc motor, it is easiest to do on a separately excited motor, where the field winding has separate. For a permanent magnet dc motor just reverse the polarity of the supply voltage. Regulation from the series 20h, using armature feedback, will be 2% of base speed. Db with a short dcib kick at the very end to finish the job is probably the fastest way to brake an ac motor electrically and safely. In this method, a brake is applied to a watercooled pulley mounted on the motor shaft as shown in fig. 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. Electricalnotes4u is a blog for electrical engineering students who want to learn electrical engineering online. Do not stand in front of the brakedrum when the supply to the loadtest circuit is switched off.
It is a full load test and it requires two identical machines which are coupled to each other. Spring balances s 1 and s 2 are kept in zero output. What is the difference between dc braking and dynamic braking. We will provide you notes on all major subject of electrical engineering. Here you get the clear idea about the electrical engineering laboratory. That means that the motor itself is used for braking, not some brake pads through mechanical means. Dc compound motor three point starter schematic diagram circuit diagram load test on dc compound generator 39. Dc compound motor definition, types, applications, equations. The power required to test a large machine is small. If the spring balance reading is s kgwt and the suspended mass has a weight of w kgwt, then. Give the expressions for various torques in dc motors.
Compound wound dc motor or dc compound motor electrical4u. Generally, this test can be done for the low rated dc machines. 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. Prepare a list of apparatus required based on the name plate details and circuitdiagram in the following format. Brake test on dc shunt motor electric motor electrical engineering. To obtain the performance characteristics of a dc shunt motor by load test. Seeing that a compound dc motor is basically a combination of a shunt wound dc motor and a series wound dc motor, it inherently acquires, to some extent, the advantages of these two categories of motors. If you have a dc motor that is malfunctioning or drawing and bleeding power through the wires, there are tests that can be done to test the efficacy of the dc motor. The brake test is the one kind of load test on dc shunt motor. Electrical machinel dc laboratory manual grietelectrical and. Dc injection braking is a braking system used with 3. One end of the rope is fixed to the floor via a spring balance s and a known mass is suspended at the other. Brake test procedures air operated brakes this system is operated by air from a compressor off the engine.
The power that a dc machine receives is called the input and the power it gives out is called the output. Hello electrical people, you already know about the different types of motors that are available today and in this article, i shall discuss about the various techniques used to stop a dc motor or to bring it to rest as we cut off the supply. In case of dc shunt motors, armature is disconnected from the supply and a rheostat variable resistor is connected across it. To conduct load test on dc compound motor and to find its efficiency. Brake test on dc compound motor free download as word doc. Introduction a series dc motor is a motor whose filed windings consists of a relatively few turns connected in series with the armature circuit. Brake test on dc compound motor electric motor electrical.
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