Turn on thread page Beta

help pls - i know its physics but im really desperate and hopw that sum of u do physi watch

    • Thread Starter
    Offline

    2
    ReputationRep:
    please help - the spec says - a qualitative understanding of the back emf in motors. these re simple motors i believe.
    if anyone has any idea pls let me know cos i don't - thanks so much :confused:
    Offline

    4
    ReputationRep:
    The motor rotates because there is a current moving in a magnetic field, and its direction determined by fleming's left hand rule. However, whenever a coil of wire moves in a megnetic field an emf is generated (as in a dynamo), and the direction of current induced is determined by the right hand rule . Thus when a motor spins, some emf is induced in the opposite direction to the input current, which is the back emf.
 
 
 
The home of Results and Clearing

3,065

people online now

1,567,000

students helped last year

University open days

  1. Bournemouth University
    Clearing Open Day Undergraduate
    Wed, 22 Aug '18
  2. University of Buckingham
    Postgraduate Open Evening Postgraduate
    Thu, 23 Aug '18
  3. University of Glasgow
    All Subjects Undergraduate
    Tue, 28 Aug '18
Poll
How are you feeling about GCSE results day?
Useful resources

Make your revision easier

Maths

Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

Equations

How to use LaTex

Writing equations the easy way

Student revising

Study habits of A* students

Top tips from students who have already aced their exams

Study Planner

Create your own Study Planner

Never miss a deadline again

Polling station sign

Thinking about a maths degree?

Chat with other maths applicants

Can you help? Study help unanswered threads

Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.