FLYWHEELS AND GOVERNORS

FLYWHEEL

A flywheel may be a robot specifically designed to efficiently store rotational energy (kinetic energy), which is proportional to the square of its rotational speed and its mass. Flywheels resist changes in rotational speed by their moment of inertia and so as to vary a flywheel's stored energy (without changing its mass) its rotational speed must be increased or decreased. Since flywheels act as energy storage devices, they're the kinetic-energy-storage analogue to electrical inductors, for instance, which are a kind of accumulator. Like other sorts of accumulators, flywheels smooth the ripple in power output, providing surges of high power output as needed, absorbing surges of high power input (system-generated power) as needed, and during this way act as low-pass filters on the mechanical velocity (angular, or otherwise) of the system.

• Smoothing the facility output of an energy source. for instance, flywheels are utilized in reciprocating engines because the active torque from the individual pistons is intermittent.
• Energy storage systems
• Delivering energy at rates beyond the power of an energy source. this is often achieved by collecting energy during a flywheel over time then releasing it quickly, at rates that exceed the skills of the energy source.
• Controlling the orientation of a system, gyroscope and reaction wheel.

ADVANTAGES OF FLYWHEELS

•      “High power density

•           High energy density

•           The lifetime of the flywheel is nearly independent of the depth of the charge and discharge cycle.   No periodic maintenance is required, easily and inexpensively maintain short recharge time

•           Flywheel systems aren't sensitive to temperature since they're operating during a vacuum   containment”

•         Unlike conventional coal and gas generators, which have an efficiency ratio of 35-40%, the flywheel operates at upwards of 85-90% efficiently. 

•       Flywheels are highly reliable, safe, long life, energy-efficient and non-polluting

•         The increasing focus and intermittent nature of renewable sources increase the demand for energy storage, like flywheels

•       “Much higher charging and discharging rate ready to cyclic discharge to zero energy without degrading

•          High power output. Large energy storage capacity. Less overall cost.

•         Power compensation is extremely effective. The system cost is often kept minimum by optimum use of small capacity flywheel energy storage system.

            DISADVANTAGES OF FLYWHEELS

•  The complexity of durable and low loss bearings. Mechanical stress and fatigue limits
• Material limits at around 700 M/Sec tip speed
• Potentially hazardous failure modes
•  Short discharge time” 
• Current Flywheels have low specific energy
•  There are safety concerns associated with flywheels due to their high-speed rotor and the possibility of it breaking loose & releasing all of its energy in an uncontrolled manner Flywheels are a less mature technology than chemical batteries, and the current cost is too high to make them competitive in the market” 

   APPLICATIONS

• Flywheels are often used to provide continuous power output in systems where the energy source is not continuous. For example, a flywheel is used to smooth fast angular velocity fluctuations of the crankshaft in a reciprocating engine. In this case, a crankshaft flywheel stores energy when torque is exerted on it by a firing piston and returns it to the piston to compress a fresh charge of air and fuel. 
• A flywheel may also be used to supply intermittent pulses of energy at power levels that exceed the abilities of its energy source.
• This is achieved by accumulating energy in the flywheel over a period of time, at a rate that is compatible with the energy source and then releasing energy at a much higher rate over a relatively short time when it is needed. For example, flywheels are used in power hammers and riveting machines.

 

 GOVERNORS

A      A governor, or speed limiter or controller, maybe a device wont to measure and regulate the speed of a               machine, like an engine. A classic example is that the centrifugal governor also referred to as the Watt or fly-ball governor on a reciprocating external-combustion engine, which uses the effect of inertial force on rotating weights driven by the machine output shaft to manage its speed by altering the input flow of steam.

centrifugal governours were wont to regulate the space and pressure between millstones in windmills since the 17th century. Early steam engines employed a purely reciprocating motion and were used for pumping water – an application that would tolerate variations within the working speed.

FUNCTION OF GOVERNOR

The function of a governor is to regulate the mean speed of an engine, when there are variations in the load e.g. when the load on an engine increases, its speed decreases, therefore it becomes necessary to increase the supply of working fluid. On the other hand, when the load on the engine decreases, its speed increases and thus less working fluid is required. The governor automatically controls the supply of working fluid to the engine with the varying load conditions and keeps the mean speed within certain limits

ADVANTAGES

They can be used when it is not necessary to maintain an exact speed depending on the load. They are simple in construction and have only a few parts.

They maintain a constant speed of the prime mover

DISADVANTAGES

variation of speed occurs due to fluctuation of load

TYPES OF GOVERNORS

• Mechanical governors
• Hydraulic governors 
• Electro-Hydraulic governors

• APPLICATIONS OF GOVERNORS

Example uses

• 3.1Aircraft
• 3.2Small engines
• 3.3Turbine controls
• 3.4Electrical generator
• 3.5Elevator

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      DIFFERENCE BETWEEN FLYWHEEL AND GOVERNOR