• Best of luck to the class of 2024 for their HSC exams. You got this!
    Let us know your thoughts on the HSC exams here
  • YOU can help the next generation of students in the community!
    Share your trial papers and notes on our Notes & Resources page
MedVision ad

DC Motors Question (1 Viewer)

robbo845

New Member
Joined
Feb 6, 2010
Messages
6
Gender
Male
HSC
2011
What would happen in a simple dc electric motor if you changed the current to AC and why. Thanks in advance
 

rawrence

Member
Joined
Sep 14, 2010
Messages
171
Location
Auxiliary Circle
Gender
Male
HSC
2011
A DC motor uses a coil in a permanent magnetic field, a split ring commutator is used to reverse direction of current every half revolution, if you supply AC then you reverse direction of current 50 times a second. It won't spin and it won't work
 

Amogh

Member
Joined
May 16, 2009
Messages
751
Gender
Undisclosed
HSC
N/A
To my understanding, it will oscillate back and forth in accordance with the frequency of the AC supply.
A DC motor is made in such a manner such that the split ring commutator reverses the flow of current every half a revolution (and ensure a constant direction of rotation). AC current reverses it's direction periodically regardless. So as the AC current direction changes, the split ring commutator would reciprocate the direction - meaning that a constant direction of current is maintained. Momentum of the coil should keep it moving in a certain direction untill the AC current changes direction.
 

robbo845

New Member
Joined
Feb 6, 2010
Messages
6
Gender
Male
HSC
2011
So if AC current changes direction 50 times per second there would be no way to ensure that it changes direction at the same that the coil(rotor) has completed a half turn, and subsequently you would have a sporadic motor rather than a continously freeflowing one?
 

OmmU

★ BoS Deity ★
Joined
Jan 21, 2011
Messages
404
Location
Middleofnowhere
Gender
Male
HSC
2011
Uni Grad
2017
So if AC current changes direction 50 times per second there would be no way to ensure that it changes direction at the same that the coil(rotor) has completed a half turn, and subsequently you would have a sporadic motor rather than a continously freeflowing one?
Yes, it will appear to be still and not moving.
 

sameerali

New Member
Joined
Jun 28, 2010
Messages
1
Gender
Male
HSC
2011
when dc electric motor current is changed from DC to AC, it will stop working.
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top