190104c magnetism Flashcards
characteristics of flux lines are
- they travel from north to south
- they can not be insulated
- they at like rubber bands and follow the shortest path
- like poles repel and unlike poles atract
what does permeability (used in reference to magnetic fields) mean
when a material has the ability to concentrate flux lines
iron, alloy, nickel, cobalt (ferromagnetic)
magnetic reluctance means
the ability of a material to resist concentration of magnetic flux lines
permanent magnatism happens when
electron orbits align
permanent magnets lose they strength when exposed to
- alternating magnetic field
- heat
- physical shock
when looking for current direction what does the “X” and “.” mean
- “X” means current moves IN
- “.” means current comes OUT
what happens when you have current flowing in a conductor (in regards to magnetism)
you have a magnetic field surrounding the conductor at right angles
when you have current flowing in two conductor in the same direction, do they attract or repel?
attract
when you have current flowing in two conductor in opposite directions, do they attract or repel?
repel
what’s a electromagnet
it’s a current carrying coil wrapped around a ferromagnetic core
strength of an electromagnet is produced by
- number of turns of wire within the coil
- voltage applied
- type of core material
what does relay do
allows a real small amount of current in the coil to control a much larger current through its contacts
what does a solenoid do
- a solenoid is a current carrying coil of wire that acts like a magnet to draw a movable iron core into a coil
motor principle states
the current carrying conductor within a magnetic field will move to an area of the weaker magnetic field
whats electromagnetic induction
the process of producing voltages by moving magnetic fields though conductors is called electromagnetic induction (alternator)
