MY CART (5)

ITEM
DETAILS
MRP
DISCOUNT
FINAL PRICE
Total Price:

There are no items in this cart.
Continue Shopping
                   

i often confused how to relate  between speed, torque, current, and voltage in a dc machine. for example when ew write the power equation P= 2(pi)NT/60 =VI.


from this eqation can I consider both N and T are directly related to current?


I know that the answer is NO. because N and T are always inversly related. but why?


can any one please cleare my confusion.

4 years ago

Share

Answers : (2)

                                        

Dear student,


Here is the basic principle for your understanding:


he force F on a wire of length L carrying a current i in a magnetic field B is iLB times the sine of the angle between B and i, which would be 90° if the field were uniformly vertical. The direction of F comes from the right hand rule*, as shown here. The two forces shown here are equal and opposite, but they are displaced vertically, so they exert a torque. (The forces on the other two sides of the coil act along the same line and so exert no torque.)



    * A number of different nmemonics are used to remember the direction of the force. Some use the right hand, some the left. For students who know vector multiplication, it is easy to use the Lorentz force directly:  F  =  q v X B ,  whence F  =  i dL X B . That is the origin of the diagram shown here.

The coil can also be considered as a magnetic dipole, or a little electromagnet, as indicated by the arrow SN: curl the fingers of your right hand in the direction of the current, and your thumb is the North pole. In the sketch at right, the electromagnet formed by the coil of the rotor is represented as a permanent magnet, and the same torque (North attracts South) is seen to be that acting to align the central magnet.


 

















Please feel free to ask your queries here. We are all IITians and here to help you in your IIT JEE preparation.


All the best.


Win exciting gifts by answering the questions on Discussion Forum. So help discuss any query on askiitians forum and become an Elite Expert League askiitian.


Now you score 5+15 POINTS by uploading your Pic and Downloading the Askiitians Toolbar  respectively : Click here to download the toolbar..


 


Askiitians Expert


Sagar Singh


B.Tech, IIT Delhi
















4 years ago
                                        

dear student,


DC motors are the simplest type; given a constant voltage, they run to a steady speed and steady current (electric torque= constant * current for DC motors).

If you need to control the torque (current), you use a current sensor (a resistor) as feedback to control the current.

If you need to control the speed, you use a speed sensor (tachometer, encoder etc) as a feedback to control the speed


Don’t forget to approve the answer if it is beneficial to you… !!


We are all IITians and here to help you in your IIT JEE preparation.


Now you can win exciting gifts by answering the questions on Discussion Forum. So help discuss any query on askiitians forum and become an Elite Expert League askiitian.


Now you score 5+15 POINTS by uploading your Pic and Downloading the Askiitians Toolbar : Click here to download the toolbar.. 


AMAN BANSAL               

4 years ago

Post Your Answer

More Questions On Electromagnetic Induction

Ask Experts

Have any Question? Ask Experts

Post Question

 
 
Answer ‘n’ Earn
Attractive Gift
Vouchers
To Win!!!
Click Here for details
A thin circular ring of area A is held perpendicular to a uniform magnetic field of induction B. A small cut is made in the ring and a galvanometer is connected across the ends such that the...
 
 
The current induced will be i = |e| / R ? i = 1/ R d ? /dt But i = dq / dt ? dq / dt = 1/R d ? / dt ? ? dq = 1/R ? d ? ? q = BA/R Normal 0 false false false EN-US X-NONE X-NONE
  img
Navjyot Kalra 11 months ago
please see the image......
 
 
p { margin-bottom: 0.25cm; line-height: 120%; } From the relation . Here ε = emf produced in the coil n = number of turns = 1 B = magnetic field induction = 0.010 T A = area of the coil = π...
 
Mallikarjun Maram one month ago
Question attached in pic [ALTS-6 Q40]
 
 
you van call on 011 40360360 for all details
 
vanaya 6 months ago
 
Sorry i forgot to attach the question... And there is no delete/edit button,so had to leave it blank..
 
ANMOL SETH 6 months ago
The electric potential due to a charged sphere of radius 2.0 cm is 400V at a distance of 10 cm from the centre. What will be the electric field at a distance of 20 cm from the centre of the...
 
 
p { margin-bottom: 0.25cm; line-height: 120%; } Potential due to a spherical charge distribution at distance r 1 is given by Magnitude of electric field due to spherical charge distribution...
 
Mallikarjun Maram 5 months ago
if R and Hare the horizontal range and maximum hieght attained by a projectile, then its speed for projection is?
 
 
Dear student, The Range and vertical height would be given by the relation: Hence, Using this, we can find the speed of projection. Regards
  img
Sumit Majumdar 7 months ago
 
sir but the answer given in the key is under root 2gH +R 2 g/8H sir please explain in detail?
 
shrilekha sharma 7 months ago
Two uniform rods of equal lengths (l) and equal masses have coefficient of linear expansion α and 2α are placed in contact on a smooth horizontal surface as shown. The temperature of system...
 
 
According to the law of thermal expansion, the change in length is linear function of change of temperature. In this case, we will assume the junction temperature ans also, change in length...
  img
Saurabh Kumar 2 months ago
View all Questions »