Ward Leonard Method

Ward Leonard's method is introduced by Henry Ward Leonard in 1891. Ward Leonard's method of speed control is employed for controlling the speed of a DC motor. it's a basic armature control method.

This system is consisting of a DC motor M and is powered by a DC generator G. during this method the speed of the DC motor (M) is controlled by applying a variable voltage across its armature.

This variable voltage is obtained employing a motor-generator set which consists of motor M., (either AC or DC motor) directly including the generator G. it's a really widely used method of speed control of DC motor.

Principle of Ward Leonard Method

The basic connection diagram of the Ward Leonard speed system is shown in the figure below. The speed of motor M is to be controlled which is powered by generator G.

The shunt field of motor M is connected across the DC supply lines. Now, generator G is driven by motor M, The speed of motor M is Constant. When the output voltage of the generator is fed to motor M, then the motor starts to rotate.

When the output voltage of the generator varies then the speed of the motor also varies. Now controlling the output voltage of the generator the speed of the motor also can be controlled.

The direction of rotation of the motor M is often reversed by excitation of the current of the generator and it can be done with the help of the reversing switch R.S. But the motor-generator set must run within the same direction.

Advantages of Ward Leonard Method

1. it's a really smooth speed system over a really wide selection (from zero to normal speed of the motor).

2. The speed is often controlled in both the direction of rotation of the motor easily.

3. The motor can run with uniform acceleration.

4. Speed regulation of the DC motor during this Ward Leonard system is extremely good.

5. It has inherent regenerative braking properties.

Disadvantages of the Ward Leonard Method

I. The system is very costly because two extra machines (motor-generator set) are required.

2. The overall efficiency of the system is not sufficient especially if it is lightly loaded.

3. Larger size and weight. Requires more floor area.

4. Frequent maintenance.

5. The drive produces more noise.

Application of Ward Leonard Method

This Ward Leonard method of the speed system is employed where very wide and really sensitive speed control may be a of DC motor in both the direction of rotation is required.

This speed system is especially utilized in colliery winders, cranes, electric excavators, mine hoists, elevators, steel rolling mills, paper machines, diesel locomotives, etc.

RS Aggarwal Aptitude Book PDF Free Download

RS Aggarwal Aptitude Book PDF Free Download RS Agarwal Aptitude Book PDF Free Download: Quantitative Aptitude by R.S Aggarwal is a standout amongst the most inclining books among the hopefuls getting ready for Bank PO, PO, MBA, RBI, IBPS, CAT, SSC, IAS, PSC, Hotel Management, Railway Recruitment Exams, and other aggressive and placement tests. This book is suggested by different specialists in this field. This book covers relatively every theme which is being requested for the focused exams. On the off chance that you are looking to Download RS Aggarwal Quantitative Aptitude PDF's most recent version with the expectation of complimentary then you appear to be at the correct place. Download PDF RS Agarwal Aptitude Book PDF Free Download This book covers Problems on Surds and Indices, Simplification, Numbers and Ages, Pipes and Cisterns, Boats and Streams, Problems on Trains, Simple and Compound Interests, Time and Work, Permutations and Combination, Clocks, Odd Man Out, Heights

Limitations of Terzaghi Theory

Limitations of Terzaghi Theory The value of the coefficient of consolidation has been assumed to be constant. The distance d of the drainage path cannot be measured accurately in the field. The thickness of the deposit is generally variable, and an average value has to be estimated. There is sometimes difficulty 1n locating the drainage face, and sometimes thin previous seams that can act as good drainage faces are missed in the boring operations. The equation is based on the assumption that the consolidation is one-dimensional. In the field, the consolidation is generally 3-dimensional. The lateral drainage may have a significant effect on the time rate of consolidation. The initial consolidation and secondary consolidation have been neglected. Sometimes these form an important part of the total consolidation. In actual practice, the pressure distribution may be far from linear or uniform.

Comparison between VSI and CSI

Comparison between VSI and CSI In power electronic systems, inverters are an essential component that converts direct current (DC) into alternating current (AC). There are two main types of inverters used in power electronic systems: Voltage Source Inverters (VSI) and Current Source Inverters (CSI). Both have their own unique advantages and disadvantages, and the choice of which to use depends on the specific application and the desired outcome. Comparisons between voltage source inverters and current source inverters are as follows. In voltage source inverters, the input voltage is maintained constant and the amplitude of the output voltage does not depend on the load. However, the waveform of load current, as well as its magnitude, depends upon the nature of load impedance. In current source inverters (CSI), the input current is constant but adjustable. The amplitude of output current from CSI is freelance of the load. However, the magnitude of output voltage and its undulation outp

Self Study World

Search This Blog