Hartnell governor: Definition, Working, Diagram, Parts [with pdf]

What is Hartnell Governor?

1] Hartnell governor is a type of spring-loaded centrifugal governor.

2] In Hartnell governor, the downward force on the sleeve is applied by spring. This downward force can be adjusted by applying compression to the spring by adjusting the nut on the frame.

3] In this type of governor, spring is used to apply load on the sleeve while in other cases dead weight is used like in porter and proell governor.

4] In this type of governor, the mean speed of the engine is adjusted by adjusting the load on the spring. 

5] Because of spring, we can adjust the mean speed of the engine while in the case of dead-weight-loaded governors it is not possible to adjust the mean speed.

6] It is smaller in size as compared to other governors. 

7] Because of the adjustable spring load, the size of flyballs is also less compared to another governor.

8] As it is spring-loaded, It doesn’t require gravitational force to return to the initial position after lowering of speed. Hence it is possible to mount it in an inclined or horizontal position.

9] Because of the presence of rollers at the sleeve surface it has less frictional resistance.

History:-

Hartnell governor is invented by the scientist Hartnell in 1875.

Hartnell governor diagram:-

Hartnell governor diagram
Hartnell-governor-diagram

Construction:-

It is consists of the following parts:- 

1] Bell crank lever:- The bell crank lever is pivoted to the frame. It has a flyball mounted on the vertical arm & the horizontal arm is connected to the sleeve.

2] Flyball or Governor ball:- These are mounted onto the vertical arm of the bell crank lever.

The weight of flyballs is comparatively lower than other governors.

3] Spring & Nut:- Spring is a helical coil spring that is enclosed into the frame.

It is used to apply downward force onto the sleeve.

Because of nut & spring, the downward force on the sleeve can be adjusted because of which means the speed of the engine can be adjusted.

The nut is mounted onto the frame to adjust the compression of the spring to apply load on the sleeve.

4] Sleeve:- It is the basic component of the governor that is mounted on the spindle of the governor.

The horizontal arm of the bell crank lever is connected to the sleeve by means of a roller. 

The movement of the sleeve is used to adjust the supply of fuel to the engine.

5] Frame:- The frame is used to holds bell crank levers & spring.

Hartnell governor is a type of spring-loaded centrifugal governor. It is smaller in construction as compared to the dead-weight governor.

It consists of a bell crank lever, pivoted to the frame. It has a flyball mounted on a vertical arm & a horizontal arm is inserted into the slot of the sleeve by means of a roller.

The spring is mounted onto the spindle between the frame & sleeve.

Hartnell governor working:-

Case 1: When the load on the engine increases

When the load on the engine increases, the speed of the engine decreases.

Because of the decrease in engine speed, centrifugal force on flyball decreases. And flyballs are moved inside. Hence load on spring decreases and the length of the spring extends.

 It results in lowering of the sleeve on the spindle, hence the supply of fuel to the engine increases, and the speed of the engine increases to the mean speed.

Case 2: When the load on the engine decreases

When the load on the engine decreases, the speed of the engine increases.

Because of the increase in engine speed, centrifugal force on flyball increases. And flyballs are moved outside. Hence load on spring increases and the length of spring decreases.

 It results in the upward movement of the sleeve on the spindle, hence the supply of fuel to the engine decreases, and the speed of the engine decreases to the mean speed.

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