Rotational Kinetic energy to Electrical energy

In summary, to slow a motor with WK^2 = 4 lb-ft from 5400 RPM to 1530 RPM, which is 0.85 times the base speed of 1800 RPM, you would need to absorb approximately 2197 J of electrical energy. This calculation is based on the difference in kinetic energy between the two speeds, using the formula Ke = 1/2 * Inertia * omega^2. The formula P = W/t could potentially be used to calculate the electrical energy, but a time value is needed which is not provided in the given information.
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danboy
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Homework Statement


I have a motor with WK^2 = 4 lb-ft turning at 5400 RPM (3 * base speed) and I want to slow it to 1530 RPM (.85 * base speed). The motor is a 25HP 4 pole with a base speed of 1800 RPM.

How much electrical energy must I absorb?

Homework Equations





The Attempt at a Solution


I have calculated the kinetic energy of the motor @ 5400 RPM and 1530 RPM using
Ke = 1/2 * Inertia * omega^2 and found the total Rotational energy lost. For Ke @ 5400 RPM I have calculated 3067 J and @1530 RPM I have calculated 869 J for a difference of 2197 J.
 
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  • #2
Now I am not sure if I should use the formula P = W/t to calculate the electrical energy and how I would do that since the time is not given.
 

What is rotational kinetic energy?

Rotational kinetic energy is the energy an object possesses due to its rotational motion. It is a form of kinetic energy that is associated with the rotation of an object around an axis.

How is rotational kinetic energy converted to electrical energy?

Rotational kinetic energy can be converted to electrical energy through the use of a generator. The rotational motion of a turbine or other rotating component is used to turn a coil of wire within a magnetic field, creating an electrical current.

What are some examples of rotational kinetic energy being converted to electrical energy?

Some examples of this conversion include wind turbines, hydroelectric dams, and steam turbines in power plants. In these cases, the rotational motion of blades or turbines is used to generate electricity.

What are the advantages of using rotational kinetic energy to generate electricity?

One advantage is that rotational kinetic energy can be harnessed from various sources such as wind, water, or steam. This allows for a diverse range of renewable energy options. Additionally, rotational kinetic energy is a relatively clean and efficient form of energy.

Are there any limitations to using rotational kinetic energy for electricity generation?

One limitation is that it requires a consistent and strong source of rotational motion to generate a significant amount of electrical energy. This means that not all locations or environments may be suitable for harnessing this type of energy. Additionally, the initial cost of building and maintaining the necessary equipment can be high.

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