electrostatic motors - Page 1
Forum section: electronics / projects

author: coppercone2
author_rank: Super Contributor
timestamp: October 22, 2024, 01:06:15 am
content: https://hardware.slashdot.org/story/24/10/20/0047204/electric-motors-are-about-to-get-a-major-upgrade---thanks-to-benjamin-franklinWhat do you think of MOSFET like motors? Are they going to take over current type motors?Leading the effort to resuscitate Franklin’s concept for motors big enough to use in industrial applications is C-Motive Technologies in Middleton, Wis. It is a 16-person startup founded by a pair of University of Wisconsin engineers named Justin Reed and Daniel Ludois who spent years tinkering with electrostatic motors to see if they could be improved.https://www.msn.com/en-us/money/markets/electric-motors-are-about-to-get-a-major-upgrade-thanks-to-benjamin-franklin/ar-AA1sx6EQ"But the secret sauce of C-Motive’s motors is, in a sense, an actual secret sauce. Dogged exploration of combinations of various readily available industrial organic fluids led to a proprietary mix that can both multiply the strength of the electric field and insulate the motor’s spinning parts from each other—all without adding too much friction—says C-Motive Chief Executive Matt Maroon."So it has to do with submerging everything in a dielectric fluid of some kind, and otherwise using standard materials, I thought it would be special ceramics.Can a dielectric fluid get polarized like a dielectric solid? Will these motors do funny things when you turn them off, or accidentally DC bias them for a while?What is the secret to a high K dielectric fluid. Can it be a nanoparticle slurry?

author: Kleinstein
author_rank: Super Contributor
timestamp: October 22, 2024, 09:44:33 am
content: One can get a relatively high K in fluid if the molekules are polar, like water. AFAIR water has a K or around 70. A problem can however be, that a highly polar liquid may also be capable of dissolving ions and this way get conductive at least a little.Suspending particles is likely not a good idea, as this may get abrasive.I am still a bit sceptical for practical use, as the electrostatic forces are relatively small. If at all it may work at the very small scale - this also makes it feasible to use a bit higher frequency and this way get a bit more power. At the small scale magnetic motors get worse and get less attractive.The other condender at small scale are piezo motors, but these can have durability limitations.

author: iMo
author_rank: Super Contributor
timestamp: October 22, 2024, 09:56:59 am
content: Afaik the motors single (or more) cell organisms are using are made that way..

author: Nominal Animal
author_rank: Super Contributor
timestamp: October 22, 2024, 11:23:59 am
content: I was thinking of dielectric oils, but their K is < 10, AFAIK. Maybe a byproduct of low viscosity EDM fluid research?

author: jpanhalt
author_rank: Super Contributor
timestamp: October 22, 2024, 11:35:59 am
content: Here's a listing for some solvent polarities and dielectric constants:https://people.chem.umass.edu/xray/solvent.htmlPresumably, for reasons mentioned, one would want to avoid solvents with hydroxyl groups like water and alcohols. NMP, DMSO, DMF and others come to mind. It's also possible they developed their own liquids. An August report stated they reached 0.5 HP:https://spectrum.ieee.org/electrostatic-motor.

author: Marco
author_rank: Super Contributor
timestamp: October 22, 2024, 11:53:51 am
content: Quote from: coppercone2 on October 22, 2024, 01:06:15 amThat's kind of the point, but unlike solids the molecules can just flip around quite easily.I think this could be interesting for steppers. Relatively low rpm, which it requires any way, and at 0 rpm it uses no power but still has torque.

author: coppercone2
author_rank: Super Contributor
timestamp: October 22, 2024, 12:17:57 pm
content: and having a 2kV power supply at force is kinda dangerous too. Microwaves have a bad reputation and their stinky to work on. You will have all sorts of people fucking with things they should not touch when a electrostatic motor breaks.

author: Marco
author_rank: Super Contributor
timestamp: October 23, 2024, 03:40:11 pm
content: Philips wrotea nice reviewon electrostatic motors explaining some of the fundamental limitations (hosted by a tube audio company).I was thinking "can't increasing the number of poles just increase the power, by increasing the switching frequency" but on reflection the distance to the stator has to decrease as the poles increase ... which reduces max voltage and wipes out your gains. Only oil and vacuum can make these motors power density competitive at macroscopic scale.

author: TimFox
author_rank: Super Contributor
timestamp: October 23, 2024, 03:54:53 pm
content: An example of electrostatic force on a dielectric fluid:Many years ago, when building an oil-filled high-voltage resistor in a glass cylinder with machined acrylic ends, I carefully sealed the end plates to the cylinder with O-rings, but had the high-voltage plug enter the top plate with a slip fit.As soon as I applied voltage to the top, the transformer oil filling started flowing upwards along the outside of the plug's insulated cylinder.Left to its own inclination, the dielectric moved to a location with lower energy.