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GATE 2016 ME (ME2) – Question 22

Machine Design · Brakes and clutches · 1 mark · Multiple choice

For the brake shown in the figure, which one of the following is TRUE?

Diagram for GATE 2016 ME (ME2) question 22
  1. Self energizing for clockwise rotation of the drum
  2. Self energizing for anti-clockwise rotation of the drum
  3. Self energizing for rotation in either direction of the drum
  4. Not of the self energizing type

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Show answer and explanation

Correct answer: (A) Self energizing for clockwise rotation of the drum

Explanation

For clockwise drum rotation the top surface moves right, so friction on the shoe acts right. Because this force is above the left pivot, it gives a clockwise moment that assists the applied downward lever force in pressing the shoe onto the drum. Thus **clockwise rotation, A**, is self-energising; reversing rotation makes friction oppose application.