Path: ...!2.eu.feeder.erje.net!3.eu.feeder.erje.net!feeder.erje.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Jeroen Belleman Newsgroups: sci.electronics.design Subject: Re: Solar powered electrostatic motor drone ?? Date: Fri, 19 Jul 2024 17:41:09 +0200 Organization: A noiseless patient Spider Lines: 108 Message-ID: References: <1qwwjrq.1j72zdkfee00kN%liz@poppyrecords.invalid.invalid> <86oi9j9sojojf8qinhranoclb3mpoaj5ag@4ax.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Fri, 19 Jul 2024 17:38:40 +0200 (CEST) Injection-Info: dont-email.me; posting-host="458d03b24616e37ea8cdac84916ddbb9"; logging-data="3209590"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/iYC9ZJ+gvBBMhRD8CsVkj" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Cancel-Lock: sha1:jzLzm2xFfjUvc0Hj/guPEov08vY= Content-Language: en-US In-Reply-To: Bytes: 5364 On 7/19/24 12:00, Phil Hobbs wrote: > Jeroen Belleman wrote: >> On 7/19/24 00:54, Phil Hobbs wrote: >>> Jeroen Belleman wrote: >>>> On 7/18/24 23:59, john larkin wrote: >>>>> On Thu, 18 Jul 2024 21:49:14 -0000 (UTC), Phil Hobbs >>>>> wrote: >>>>> >>>>>> john larkin wrote: >>>>>>> On Thu, 18 Jul 2024 19:21:23 +0200, Jeroen Belleman >>>>>>> wrote: >>>>>>> >>>>>>>> On 7/18/24 18:42, Liz Tuddenham wrote: >>>>>>>>> Jeroen Belleman wrote: >>>>>>>>> >>>>>>>>>> On 7/18/24 07:46, Jan Panteltje wrote: >>>>>>>>>>> Researchers build ultralight drone that flies with onboard solar Bizarre >>>>>>>>>>> design uses a solar-powered motor that's optimized for weight. >>>>>>>>>>> https://arstechnica.com/science/2024/07/researchers-build-ultralight-dro >>>>>>>>>>> ne-that-flies-with-onboard-solar/ >>>>>>>>>>> >>>>>>>>>>> Well, ehh, unlimited flight time if any sun.. >>>>>>>>>>> Looks funny. >>>>>>>>>>> 4.5V to 9 kV power converter... >>>>>>>>>> >>>>>>>>>> I wonder if electrostatic motors would have been as practical >>>>>>>>>> as electromagnetic motors if the history of motor design had >>>>>>>>>> taken a different turn a century or two ago. >>>>>>>>> >>>>>>>>> I think Philips dabbled with them many decades ago. A report will be >>>>>>>>> somewhere in the Philips Technical Review. >>>>>>>>> >>>>>>>>> >>>>>>>> >>>>>>>> Thanks for that hint. The Philips Technical Review is a treasure >>>>>>>> trove of interesting stuff. >>>>>>>> >>>>>>>> I found a paper by B. Boll¥ on electrostatic motors: >>>>>>>> . >>>>>>>> >>>>>>>> Jeroen Belleman >>>>>>>> >>>>>>> >>>>>>> I wonder how many orders of magnitude an electrostatic motor is worse >>>>>>> than a magnetic motor, in some criterion like power per volume or >>>>>>> power per dollar. 6 maybe? >>>>>>> >>>>>>> >>>>>> >>>>>> The main problem for outdoor use is going to be leakage, I expect. >>>>>> >>>>>> Could be useful if you forget where you parked your car at the airport. ;) >>>>>> >>>>>> Cheers >>>>>> >>>>>> Phil Hobbs >>>>> >>>>> Seems to me that an electrostatic motor will need switching of many >>>>> kilovolts into the electrodes. Charging and discharging, efficiently. >>>>> >>>>> https://www.c-motive.com/ >>>>> >>>>> That alone seems messy to me. >>>>> >>>>> >>>> >>>> >>>> I was thinking of stacks of many stator disks with conductive sectors, >>>> interleaved with as many rotor disks. Running voltage would be a few >>>> hundred volts, maybe up to a kV. Commutation can be mechanical or >>>> electronic. If fed with AC, commutation is implicit, but some tricks >>>> would be needed to create a starting torque. >>>> >>>> Leakage in humid condition can be dealt with by covering the disks >>>> with an insulating coating. The problem is not so different from >>>> magnetic motors >>> >>> …in a universe where there are magnetic monopoles. ;) >>> >>> Cheers >>> >>> Phil Hobbs >>> >> >> Where did that come from? Why do you think monopoles should >> be involved? >> >> Jeroen Belleman >> > > Magnetostatics and electrostatics are not the same in our world, because > there’s no free magnetic charge (i. e. monopoles) to cause magnetic > leakage. > > Cheers > > Phil Hobbs > OK, true, but I don't see why that affects the practicality of electrostatic motors. In fact, if you remove the motor drive of a pelletron, it will happily run in reverse, driven by the acccumulated charge on the high-voltage electrode. (I'm not suggesting that a pelletron is an optimal configuration for an electrostatic motor.) Jeroen Belleman