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From: Jeroen Belleman <jeroen@nospam.please>
Newsgroups: sci.electronics.design
Subject: Re: Solar powered electrostatic motor drone ??
Date: Fri, 19 Jul 2024 17:41:09 +0200
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On 7/19/24 12:00, Phil Hobbs wrote:
> Jeroen Belleman <jeroen@nospam.please> wrote:
>> On 7/19/24 00:54, Phil Hobbs wrote:
>>> Jeroen Belleman <jeroen@nospam.please> wrote:
>>>> On 7/18/24 23:59, john larkin wrote:
>>>>> On Thu, 18 Jul 2024 21:49:14 -0000 (UTC), Phil Hobbs
>>>>> <pcdhSpamMeSenseless@electrooptical.net> wrote:
>>>>>
>>>>>> john larkin <jlarkin_highland_tech> wrote:
>>>>>>> On Thu, 18 Jul 2024 19:21:23 +0200, Jeroen Belleman
>>>>>>> <jeroen@nospam.please> wrote:
>>>>>>>
>>>>>>>> On 7/18/24 18:42, Liz Tuddenham wrote:
>>>>>>>>> Jeroen Belleman <jeroen@nospam.please> 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:
>>>>>>>> <https://pearl-hifi.com/06_Lit_Archive/02_PEARL_Arch/Vol_16/Sec_53/Philips_Tech_Review/PTechReview-30-1969-178.pdf>.
>>>>>>>>
>>>>>>>> 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