Question

A governor of Hartnell type has equal ***** of mass 3 kg, set initially at a radius of 200 mm. the arms of the ball – crank lever are 110 mm vertically and 150 mm horizontally. Find i) the initially compressive force on the spring at a radius of 200 mm at 240 r.p.m, and ii) the stiffness of the spring required to permit a sleeve movement of 4 mm on a fluctuation of 7.5% in the engine speed.

Answer 1

mass , m = 3 kg, radius. r = 200 mm = 0.2 m, a = 110 = 0.11 m,b = 150 mm = 0.5, N1 = 240 rpm, x = 4 mm.

(i) Initial compressive force on the spring (s1) :

w.k.t. the centrifugal force at the minimum speed,

For minimum position we know that,

*(ii) Stiffness of the spring () :**

Fluctuation of speed, Cs

Maximum speed, N2 = 258.7 rpm

w.k.t. the sleeve is , x = (r2 - r1)(b/a)

Centrifugal force at the maximum speed,

For maximum position w.k.t.

Stiffness of the spring,