yup. ill reply for qn 2.
Slip ring commutators are used for AC generators.
Note: DC motors, use split ring commutators, as the commutators
reverse the direction of the current every half revolution. Just
use the right hand rule, or flemings left hand rule, to determine
the direction of the torque and force.
eg.. >>>>>>>>>
o--------------X >>>>>>>
"o " represents the wire, coming out of the page
"X" represents the wire going into the page
">>>>" is the magnetic field direction
"--------" will be the armature of the motor
so if u see the above diagram, the armature will rotate in a
clockwise direction, use RH rule(suppose that current is flowing
through and its a DC motor), at that position above, the torque is
at maximum, and force on the wire is also maximum.
T=BIAnCos(@).... @ represents tither
and force experienced on a wire in a mag field: motor effect
F=BILSin(@)
.
Now, as you were saying, if a slip ring was used instead, it
means that the commutator will NOT be able to reverse the currents.
what will happen will be a standstill where the armature is at
perpendicular to the magnetic field, or as u say, vertical.
why? Cause the force and torque on both of the wires are
equal (Use the hand rule to determine), therefore, they
cancel each other out.
Resultant force = 0. no movement