Draft:Original research/Electrostatic suspension

The image is an artist concept of Gravity Probe B spacecraft in orbit around the Earth. Credit: NASA/MSFC.

Electrostatic suspension can occur whenever a voltage difference exists between two locations and a charged mass is within the space separating the two locations, where the amount of charge is sufficient to allow suspension or prevent contact with either location. The potential gradient is the local space rate of change of the electric potential, usually in units of volts per meter (V/m). An electric field is an electric potential of opposite sign. The Earth, for example, has a natural electric field.

Charges

Charge polarization is often a stationary polarization of charge induced by a dc electric field to a polarization voltage (V_p) that polarizes the material of the mass, where the switch-on and switch-off time of the dc field is usually very slow.

For some situations, the more positive the polarization, the greater the likelihood of electron transfer.

The mass shape should be circular in front of the horizontal electrodes.

Suspensions

Def. temporarily prevent from continuing is called suspend.

Def. hanging freely is called suspension.

Electrostatics

Main articles: Charges/Interactions/Electrostatics and Electrostatics

Def. the study of stationary electric charges or fields as opposed to electric currents is called electrostatics.

Def. "the branch of physics that deals with static electricity; that is, with the force exerted by an unchanging electric field upon a charged object" is called electrostatics.

Static electricity

Def. "an electric charge that has built up on an insulated body, often due to friction" or "the electric discharge from such a body" is called static electricity.

Vertical suspensions

File:Vertical suspension.png

This diagram describes the mechanical core of a torsion pendulum. Credit: E. Willemenot and P. Touboul.

"The upper electrodes are used to apply control voltages (228 V in nominal conditions). The lower electrode voltages are controlled to V_p [a dc voltage of about 10 V], so that no force attracts the mass toward the bottom."

For a gap of 0.00206 m, a proof mass of 5.40 g is successfully suspended against 1 G (of gravity) with a field of 7.7 x 10⁶ V/m. The voltage on the proof mass is nominally 10 V.

A thin gold wire is attached at the bottom of the proof mass to allow charge or voltage to be added of removed from the proof mass. The mechanical core apparently including the proof mass is made of gold coated fused silica.

Horizontal suspensions

File:Horizontal suspension.png

The diagram displays the mechanism for horizontal suspension. Credit: E. Willemenot and P. Touboul.

Three horizontal axes can be used (two for translation x and y, and rotation φ).

"The forces between the plates and the arm are proportional to the polarization voltage V_p of the proof mass [within the plate grid] and to the vertical V applied on the electrodes."

The diagram on the right includes the thin gold wire which is used to bleed off or increase the potential (charge) on the proof mass.

Electrostatic stiffnesses

"In order to have electrostatic negative stiffness as low as possible on the three horizontal degrees of freedom (x, y, φ), the electrode arrangement and shapes have been chosen in order to have electrostatic forces that do not depend on the on the proof mass position, but only on control voltages."

Parasitic forces

"[S]ome edge effects can [produce small] stiffnesses."

Water droplets in an electric field

In 1909, Robert Andrews Millikan began a series of experiments to determine the electric charge carried by a single electron. He began by measuring the course of charged water droplets in an electrical field. The results suggested that the charge on the droplets is a multiple of the elementary electric charge.

A water droplet elongates in an electric field due to electrostatic pressure, and becomes unstable when a critical field limit is reached.

Water droplets in an electric field become polarized through alignment of the polar water molecules with the external electric field and through redistribution of mobile charged particles or ions within the droplet.

Theoretical electrostatic suspensions

Def. "of, relating to, or produced by electrostatics or static electricity" is called electrostatic.

Def. a "temporary or conditional delay, interruption or discontinuation" is called a suspension.

Here's a theoretical definition:

Def. a temporary or conditional delay, interruption or discontinuation of, relating to, or produced by electrostatics or static electricity is called an electrostatic suspension.

Rocky objects

Main articles: Rocks/Rocky objects and Rocky objects

A dusty plasma of fuel nanoparticles can be electrostatically suspended. Electrostatic particulate suspension (EPS) can be used for testing spark breakdown, ignition, and quenching characteristics of a small volume powder suspension. Transient dust clouds are measured optically or assumed to have a uniform particulate distribution over a test volume so that particle concentration can be determined.

Particle clouds can be trapped and manipulated by electrostatic suspension in a Millikan condenser.

Particles of opposite polarity can be kept apart and aggregation is induced by changing the electric field.

Cluster growth into particles can occur that involves plasma negative ions and ion clustering with plasma species by electrostatic suspension and trapping.

For a given charge to mass ratio there is, in principle, no limit on the size range of electrostatic control.[9]

When dust concentrations are high, there is a tendency for a reduction in individual grain charging due to collective effects.[10][11]

Moon

At lower latitudes on or very near the surface of the Moon is a twilight haze, associated with terminator passage (sunset and sunrise), that is believed to be due to small particles moving in electrostatic suspension within a few meters of the surface.[12]

There are also some gas clouds associated with terminator passage.[13] Since the terminator is always present in the polar regions, the local environment due to these particle and gas effects may be different.[13]

Dust grains and the lunar surface are electrostatically charged by the Moon's interaction with the local plasma environment and the photoemission of electrons due to solar ultraviolet and X-radiation.[14] Dust grains on the 0.1 µm-scale have been observed at ~100 km altitude above the Moon's surface.[14] These grains may be accelerated upward through a narrow sheath region by the surface electric field.[14]

Technology

An "electrostatically suspended induction motor (ESIM) [...] possesses the rotating ability of an ordinary electrostatic induction motor, in addition to providing contactless support by electrostatic suspension."

Electrostatic suspension is used in several apparati, like the gyroscopes of the space mission Gravity Probe B, commercial gyroscopes, or space accelerometers.

Parasitic forces are associated with such a suspension.

Chargers

This is a typical simple charger. Credit: Jan airon securata.

Example is of a smart charger for AA and AAA batteries. Credit: Medvedev.

Linear induction flashlight, charged by shaking along its long axis, causing magnet (visible at right) to slide through a coil of wire (center) to generate electricity. Credit: Chetvorno.

Made by Tremont Electric, a human motion charger consists of a magnet held between two springs that can charge a battery as the device is moved up and down, such as when walking.

A pedal powered charger for mobile phones, fitted into desks has been created by a Belgian company WeWatt, for installation in public spaces, such as at airports, railway stations and universities have been installed in a number of countries on several continents. A battery charger, or recharger, is a device used to put energy into a secondary cell or rechargeable battery by forcing an electric current through it.

For a battery with a capacity of 500 mAh, a discharge rate of 5000 mA (i.e., 5 A) corresponds to a C-rate of 10 (per hour), meaning that such a current can discharge 10 such batteries in one hour; for the same battery a charge current of 250 mA corresponds to a C-rate of 1/2 (per hour), meaning that this current will increase the state of charge of this battery by 50% in one hour.

All charging and discharging of batteries generates internal heat, and the amount of heat generated is roughly proportional to the current involved (a battery's current state of charge, condition / history, etc are also factors), although, some batteries reach their full charge, cooling may also be observed.

The maximum ripple current for a typical 12 V 100 Ah VRLA battery is 5 amps. As long as the ripple current is not excessive (more than 3 to 4 times the battery manufacturer recommended level), the expected life of a ripple-charged VRLA battery will be within 3% of the life of a constant DC-charged battery.

A typical intelligent charger fast-charges a battery up to about 85% of its maximum capacity in less than an hour, then switches to trickle charging, which takes several hours to top off the battery to its full capacity.

Some chargers use pulse technology in which a series of voltage or current pulses is fed to the battery. The DC pulses have a strictly controlled rise time, pulse width, pulse repetition rate (frequency) and amplitude. This technology is said to work with any size, voltage, capacity or chemistry of batteries, including automotive and valve-regulated (VRLA) batteries.

With pulse charging, high instantaneous voltages can be applied without overheating the battery. In a Lead–acid battery, this breaks down lead-sulfate crystals, thus greatly extending the battery service life.

Several kinds of pulse charging are patented.

Some chargers use pulses to check the current battery state when the charger is first connected, then use constant current charging during fast charging, then use pulse charging as a kind of trickle charging to maintain the charge.

Capacity in Wh: Total power capacity measured by multiplying mAh by voltage.

A battery pack advertised with a 3000 mAh capacity (at 3.7 V) will produce 2220 mAh at 5 V, power losses due to efficiency of the charging circuitry also occur.

Hypotheses

1. Using the approximate charge separation between the ionosphere and Earth ground it should be possible to calculate how much charge is necessary to raise a 5,000 kg (kilogram) object above the ground between 70 m (meter) and 7000 m (meter).
2. A supercapacitor or similar device can hold up to 3300 coulombs.

See also

• Applications of power electronics (8 kB) (18 October 2019)
• Astrognosy (43 kB) (13 August 2019)
• Atmospheric sciences (39 kB) (18 October 2019)
• Balloons for astronomy (24 kB) (6 June 2019)
• Charge ontology (37 kB) (25 June 2019)
• Charges (25 kB) (13 September 2019)
• Distances (12 kB) (6 October 2019)
• Electrochemical capacitors (16 kB) (31 October 2019)
• Electron beam heating (19 kB) (31 October 2019)
• Electrospheres (14 kB) (2 November 2019)
• Electrostatic suspension (22 kB) (29 May 2019)
• Electrostatic suspension/Laboratory (13 kB) (29 March 2019)
• Geophysics (80 kB) (12 August 2019)
• Lightning (13 kB) (25 June 2019)
• Lofting technology (91 kB) (9 July 2019)
• Magnetic field reversals (55 kB) (25 July 2019)
• Measurements (3 kB) (25 June 2019)
• Mems capacitors (30 kB) (1 November 2019)
• Natural electric field of the Earth (27 kB) (23 June 2019)
• Particle fountain (11 kB) (26 May 2019)
• Repellor vehicles (42 kB) (5 August 2019)
• Shielding (10 kB) (19 August 2019)
• Spaceflights (23 kB) (23 June 2019)
• Volcanoes (95 kB) (19 September 2019)

Further reading

• E. Willemenot and P. Touboul (January 2000). "Electrostatically suspended torsion pendulum". Review of Scientific Instruments 71 (1): 310-4. http://www.mtl.mit.edu/researchgroups/mems-salon/sriram_torsion-pendulum.pdf. Retrieved 2015-01-12. 

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