Lesson 8 Review Flashcards
When a current-carrying coil is placed in a magnetic field, the magnetic field created by the current in the coil interacts with the main field, what is produced?
Torque
Torque development is dependent on what factors?
- Mag Field Strength
- # of turns in the coil
- Coil POSITION in field
Direction of the lines of Flux:
i) Around the current carrying conductor
ii) of the MAIN field
determines what?
Direction of rotation of the coil
When do we apply the Right Hand Rule for MOTORS?
determine the DIRECTION of ROTATION of the COIL
What do we use to maintain the direction of the toque developed in the same direction? How?
COMMUTATOR
coil current direction REVERSED when COIL about to stop
True or False:
More Segments = More Torque
True
Speed can be varied by what?
Current of the FIELD
True or False:
The greater the FIELD current, the greater the counter EMF, the SLOWER the rotation of the armature
True
How would you change the armature DIRECTION of ROTATION?
REVERSE Current flow/FIELD = reversed magnetism
What is a transformer?
A device used to increase or decrease the VOLTAGE in an AC circuit
Why would we use a soft-iron core for the secondary winding of a transformer?
It has better reaction
What is the turns ration?
The ratio of the primary voltage to the secondary voltage is proportional to the number of turns in the primary to the number of turns in the secondary
Ep / Es = Np / Ns
For a transformer, power in equals what?
Power out
For power input to equal power output
the current ratio is inversely proportional to the voltage ratio
Ep / Es = Is / Ip
What converts DC to AC?
INVERTERS
