Machine-translated by Google. Questions are authored in English.
Top

Discussion

Resistance commutation relies upon

  • A.the resistance of the commutator segments themselves
  • B.the rising contact resistance as the segment leaves the brush
  • C.the resistance of the armature winding itself
  • D.the resistance of the interpole winding in series

Answer: B

Correct answer: the rising contact resistance as the segment leaves the brush

As the segment slides out from under the brush the contact area shrinks, so its resistance rises steeply, and that rising resistance forces the current out of the leaving path and into the entering one. It suffices in small machines but not in large ones, where the reactance voltage is too great for resistance alone to overcome.

No comment is present. Be the first to comment.
Loading…

Post your comment

Please log in or register to post a comment.