Copper was commonly used in electromagnetic kilowatt-hour meters, in North America, until the mid 1950s by Sangamo, the largest manufacturer of meters. It was replaced by aluminum due it's lower weight, for less respense start-up torque and lower cost.
An accretion disc is a structure formed around a central object, often a black hole or a young star, as it gathers material from its surrounding environment. The material in the disc spirals inward due to gravity, releasing energy in the form of heat and light. Accretion discs play a key role in powering some of the brightest phenomena in the universe, such as quasars and X-ray binaries.
A disc. Such as:CDCD-RCD-WRCD-RomDVDDVD-RDVD-WRDVD-RomDVD-RAM
In order to give a CD another shape do the following:Preheat conventional oven at 400*FPut the CD in a container that you want it to make.Put container (with the CD inside) into the oven for 4 minutes.
The term for the moon when the whole disc is visible from Earth is "full moon." During a full moon, the sun, Earth, and moon are aligned in a way that the illuminated side of the moon is facing the Earth.
Originally, all the energy on the Earth, in the universe, really, came from the "Big Bang". Early giant stars that went supernova created all the various elements, which coalesced into the planets making up the early solar disc. This material, by Accretion, formed into the planets around a large ball of hydrogen which later became the sun. This accretion, known as a bombardment, imparted the energy of these impacts into frictional heat energy. A secondary "great catastrophe" which formed the moon imparted more heat to the Earth. Radioisotopes impart a small amount of heat to the inner planet, but this is naturally decreasing as the elements break down into more stable elements. The gravitational (tidal) pull of the moon, and to a lesser extent the sun, also imparts some frictional heat to the Earth. The remaining energy on the Earth has been transmitted by heat radiation from the sun, which, for the last 4 billion years or so, has been shining on the Earth.
The Aluminium disc in energy meter continues to slowly rotate even if no current is supplied to the current coil . This rotation of the disc is known as creep .
In some energy meters, the disc rotates slowly and continuously when there is no load.the rotation of disc without any current through current coil and only due to excitation of pressure coil is called creeping.
Aluminium is a good conductor but it is non magnetic material and therefore cannot be altered by magnetic currents and run true and hence it is preferred.
The two holes in the disc of an energy meter allow for the insertion of a small metal tab that causes the disc to rotate. As electricity flows through the meter, the disc spins in proportion to the amount of energy consumed, providing a visual representation of power usage to the user.
a small hole drilling in the disc ofenergy meter is to avoid
Keeping the speed of the rotating disc in an energy meter as low as possible helps to reduce wear and tear on the components, minimize frictional losses, and increase the longevity and accuracy of the meter. Additionally, lower speeds make it easier to accurately measure and record the energy consumed.
Typically, the rotating disc in an energy meter is made of lightweight and durable materials such as aluminum or plastic. These materials are carefully selected to ensure accurate rotation and minimal wear over time while being cost-effective for mass production.
Energy meter works on the same principle as the induction motor. An aluminium disc is placed inside a magnetic core with two limbs. One carries a voltage coil so its flux is proportional to voltage, the second carries a current coil so its flux is proportional to current. The two fluxes induce eddy currents into the disc, each of which interacts with the flux of the other to produce a torque, which accelerates the disc. This torque of course is proportional to flux × the eddy current, which equates to V × I, or power. A permanent magnet creates another eddy current resulting in a torque proportional to speed that brakes the disc, the combined result of these actions is that the speed of the disc is proportional to power, and the total number of revolutions is proportional to the energy that has passed through the meter. The disc drives a chain of gears that turn a mechanical counter, called a 'register'.
The oscillations of a copper disc in a magnetic field are lightly damped because copper is a good conductor of electricity. As the disc cuts through the magnetic field, currents are induced that create a magnetic field opposing the motion, resulting in a damping effect. However, due to the high conductivity of copper, these currents quickly dissipate the energy, leading to lightly damped oscillations.
First of all, you are referring to an energy meter, not a wattmeter. A wattmeter measures power, in watts, whereas an energy meter reads energy, in watt hours (or, more specifically, kilowatt hours). The energy company bills you for energy, not power.Having said that, the connections each instrument are the same. In fact, there are two coils inside an energy meter: a current coil, and a voltage (or potential) coil. The current coil is connected in series with the load while the voltage coil is connected in parallel with the supply voltage.The current coil measures the in-phase component of the current drawn by your load, so that the instrument always reads the true power (multiplied by time -the function of the aluminium disc) of the load -i.e. not the apparent power or reactive power.
The number of revolutions the disk in a kWh meter needs to make to produce a read increase of one unit (1 kWh) is 1000 divided by the disk constant. The disk in a meter with a 7.2 constant (Kh = 7.2) will have to make 138 and 8/9 revolutions to make the right most dial in the meter increase its read by one unit.
for a disc type (electromechanical) meter the number of disc revolutions to indicate 1 kwh would be found by the formula 1000/ Kh, the watthour constant of the meter.