Table of Contents

Design and Analysis of Centrifugal Governor : A Review

Abstract –

The function of the governor is to maintain the speed of an engine within specified limits whenever there is a variation of load. This device can be used in almost all vehicles. The objective of our investigation to identify the stress concentration areas & areas which are most susceptible to failure when governor is rotating about its axis, also the value of these stresses is measured. This analysis is carried out with the help of PRO E. The displacement of the various elements of the SPINDLE from the base is also calculated and the graphs are plotted. Effect of the “WEIGHT OF THE ARMS” is the major area of concern for our study and all the calculations are done considering the weight of the arms. Weight of the arms acts on the centroid of the arms and when the governor assembly rotates, centrifugal force starts acting on the centroid of the arms and tends to deflect the arms, this deflection or bending is to be minimized. In our work, we have done the Stress analysis on a particular configuration of governor assembly and then various materials are suggested on a theoretical basis.

Centrifugal governor

A flyweight mechanism driven by the engine is linked to the throttle and works against a spring in a fashion similar to that of the pneumatic governor, resulting in essentially identical operation. A centrifugal governor is more complex to design and produce than a pneumatic governor. However, the centrifugal design is more sensitive to speed changes and hence is better suited to engines that experience large fluctuations in loading.

DESIGN OF GOVERNOR

Design Process

Design Criteria of the Governor All the legs move exactly like one another
Its total axial deflection at 6000 rad/sec cannot exceed 2.3 mm.
Neglecting the in-plane load effects, the fundamental natural frequency to be below 2000 Hz
The lengths L1 and L2 have the following relations: 1.4*L2
<= L1 <= 2.0*L2. L1 and L2 must be reasonable and comparable. The width and thickness of all sections of the legs are constant.
The thickness and width of each leg can vary in increments of 0.25 mm
The thickness is relatively small
The height of the short sections of the legs is 4 mm.
All edges of the legs (except the ones that connect to the shaft) are straight

RESULTS AND DISCUSSION

From the stress analysis of the various parts of the governor assembly we are able to identify the stress. Governor’s axial deflection vs. angular velocity, the angular velocity of model was varied and radial displacement was obtained. For various angular velocity, the nature of deviation in radial displacement was obtained. And from our study we determined that, as the angular velocity increases the axial displacement increases.