Question 536Electricity/Electronics - QMED70% to pass
As shown in the illustration, which brush holder is of the reaction type? Illustration EL-0029
AI Explanation
The correct answer is D.
The brush holder labeled 4 in the illustration is of the reaction type. The reaction type brush holder is used in DC generators and motors, where the brushes are held in place by a spring that applies pressure against the commutator. This allows the brushes to follow the commutator as it wears down, maintaining constant contact.
The other brush holders labeled 1, 2, and 3 are not of the reaction type, as they do not use a spring-loaded mechanism to maintain brush contact with the commutator.
Related Questions
#534 In a shunt-wound DC generator, with what generator component are the shunt field windings connected in parallel with? #535 A variable shunt, connected across the series field coils of a DC compound wound generator, permits adjustment of the degree of compounding. What is this variable shunt called? #537 Which of the diagrams shown in the illustration depicts the proper method of aligning brushes on a commutator for a DC machine? Illustration EL-0057