Why flexible couping are preferred over rigid coupling?

Flexible coupling accomplishes the purpose of any coupling, but the main advantage over rigid coupling is flexible coupling is to accommodate the unavoidable misalignment between shafts in some machinery. 

The flexible coupling also allows a degree of axial movement between the coupling shafts as possible due to thermal expansion.  

As compared with a flexible coupling, the rigid coupling has limited application because rigid couplings do not have the ability to compensate for shaft misalignment, therefore, used where shafts are already positioned in precise lateral and angular alignment.


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Proell governor | Construction | Working | Equation of height

A porter governor is known as a proell governor is the two balls are fixed on the upward extensions of the lower links which are in the form of bent links BAE and CDF as shown in the figure below. 

Now, considering the equilibrium of the link BAE which is under the action of following characteristics. 

• The weight of the ball, mg
• The tension in the link AO
• The horizontal reaction of the sleeve
• The weight of sleeve and friction 1/2 (mg+f) or 1/2 (mg-f)
• The centrifugal force, mr’ᾠ² 

I is the instantaneous centre of the link BAE and take moments about I to find out the height relation for proell governor. 

N² = 895×a/h×e [ 2mg + ( mg + or – f ) ( 1+k) / 2mg ] 

Difference between watt governor and proell governor

The function of the governor is to regulate the speed of an engine when there are variations in the load. For example, when the load increases, it becomes necessary to increase the supply of working fluid and when the load decreases, less working fuel is required. Let us have a deep insight into the difference between watt governor and proell governor in this article. 

Difference between Watt and Proell Governor : 

• Watt governor is the simplest form of a centrifugal governor basically a conical pendulum with links attached to a sleeve of negligible weight and the proell governor has the balls fixed at the endpoint to the extension of the links. 
• Watt governor is pendulum-type while the proell governor is dead-weight loaded type governor. 
• The arm of watt governor may be connected to the spindle by two way, the pivot may be on the spindle axis, and pivot may be offset from the spindle axis but arms intersect while in proell governor the balls are fixed. 

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Mechanical Vs Hydraulic disc brake | Difference between mechanical and hydraulic disc brake

The function of both braking systems are the same but there is a lot of difference between these two brakes. Mechanical disc brake also known as cable-actuated brakes rely on a braided steel cable to activate the piston that causes the compression of brake pad against the rotor when the brake lever is pulled. Hydraulic disc brake used hydro or rather fluid uses a sealed fluid-filler system as a means of actuation. Let us have a deep insight into the difference between these two braking systems. 

Difference between mechanical and hydraulic brake : 

• A mechanical disc brake uses cables as a braking medium whereas hydraulic disc brake uses the fluid as a braking medium. 
• The mechanical disc brake is heavier in weight as compared to hydraulic disc brake. 
• A mechanical disc brake is less sensitive, requires more force to come to a stop and the hydraulic disc brake is more sensitive and efficient. 
• Maintainance is frequent in mechanical disc brake whereas hydraulic brake is the maintenance free. 
• Adjustment of brakes is easy in mechanical braking while complex in hydraulic braking.
• The hydraulic disc brake is expensive as compared to mechanical disc brake. 
• Hydraulic brakes give better performance for the same size rotor, but mechanical brakes are good enough if you are using a bigger rotor and set them up correctly.