MY CART (5)

Use Coupon: CART20 and get 20% off on all online Study Material

ITEM

DETAILS

MRP

DISCOUNT

FINAL PRICE

Total Price: Rs.

There are no items in this cart.

Continue Shopping

Continue Shopping

Menu

` `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.

6 years ago

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:

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

6 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 speedDon’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

6 years ago

Think You Can Provide A **Better Answer ?**

Answer & Earn Cool Goodies

Have any Question? Ask Experts

Post Question

copyright © 2006-2017 askIITians.com

info@askiitians.com