Question

For the secondary balancing of the engine, which of the condition is necessary?

(a) Secondary force polygon must be close

(b) Secondary force polygon must be open

(c) Primary force polygon must be close

(d) Primary force polygon must be open

This question was addressed to me in an interview for internship.

I'd like to ask this question from Balancing of Coupled Locomotives & Secondary Forces of Multi-cylinder Inline Engines in portion Balancing of Reciprocating Masses of Machine Dynamics

Answer 1

The correct answer is (a) Secondary force polygon must be close

For explanation: In order to achieve the secondary balancing of the engine. The sum (algebraic ) of the secondary forces must be equal to zero. In other words, the secondary force polygon must close.