Explain about direct-current machines, Electrical Engineering

Assignment Help:

Q. Explain about Direct-current machines?

Generally speaking, conventional dc generators are becoming obsolete and increasingly often are being replaced by solid-state rectifiers in most applications for which an ac supply is available. The same is not true for dc motors. The torque-speed characteristics of dc motors are what makes them extremely valuable in many industrial applications. The significant features of the dc drives include adjustable motor speed over wide ranges, constant mechanical power output or torque, rapid acceleration or deceleration, and responsiveness to feedback signals.

The dc commutator machines are built in a wide range of sizes, from small control devices with a 1-W power rating up to the enormous motors of 10,000 hp or more used in rolling-mill applications. The dcmachines today are principally applied as industrial drivemotors, particularly when high degrees of flexibility in controlling speed and torque are required. Such motors are used in steel and aluminumrollingmills, tractionmotors, overhead cranes, forklift trucks, electric trains, and golf carts.Commutatormachines are also used in portable tools supplied frombatteries, in automobiles as starter motors, in blower motors, and in control applications as actuators and speed-sensing or position-sensing devices.


Related Discussions:- Explain about direct-current machines

Develop a block diagram of an asynchronous decade counter, Q. Counting to m...

Q. Counting to moduli other than 2 is a frequent requirement, the most common being to count through the binary-coded decimal (BCD) 8421 sequence. All that is required is a four-st

Differentiate between accuracy and precision, Q. With suitable example diff...

Q. With suitable example differentiate between accuracy and precision.  Sol. Accuracy :  Accuracy is the closeness with which instrument reading approaches the true value of

Determine the speed of the motor, Q. A 10-kW, 250-V dc shunt generator, hav...

Q. A 10-kW, 250-V dc shunt generator, having an armature resistance of 0.1and a field resistance of 250 , delivers full load at rated voltage and 800 r/min. The machine is now ru

Define characteristics of discrete time systems - linear, Define Characteri...

Define Characteristics of Discrete Time Systems - Linear? A discrete-time system is said to be linear if it obeys the principles of superposition. That is, the response of a li

Energy conservation , Energy conservation: NEP envisages a voluntary a...

Energy conservation: NEP envisages a voluntary approach initially for promoting energy conservation along with emphasis on labelling of appliances. Gradually as awareness incr

Electrical drives, 'Electrical drives' is a general term that is commonly u...

'Electrical drives' is a general term that is commonly used to describe both DC and AC excited motors that provide continuous rotary motion, whilst 'electrical actuators' provide l

Use of speaker, Q. Use of Speaker? Speaker:Basically speaker is the rec...

Q. Use of Speaker? Speaker:Basically speaker is the receiver for telephone. Speaker converts electrical signals received from local loop to acoustical signals(sound waves) that

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd