Path: ...!eternal-september.org!feeder2.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail
From: Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net>
Newsgroups: sci.electronics.design
Subject: Re: switchmode gyrator
Date: Tue, 12 Nov 2024 19:48:38 -0000 (UTC)
Organization: A noiseless patient Spider
Lines: 55
Message-ID: <vh0bem$1oito$1@dont-email.me>
References: <onquijt47loo1c3krbof1mpq0l16a8afqv@4ax.com>
 <rbj6jjt0tm8m6kjmnp7akojmshrhbo3uop@4ax.com>
 <evt6jjh8utojvc9ugmi54f0qp8aehfka93@4ax.com>
 <vh07fo$1nq2q$1@dont-email.me>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Injection-Date: Tue, 12 Nov 2024 20:48:38 +0100 (CET)
Injection-Info: dont-email.me; posting-host="22fb9181e0d46df66165f390d5149356";
	logging-data="1854392"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX18qbmTucm8dIM0ze7rHbTkx"
User-Agent: NewsTap/5.5 (iPhone/iPod Touch)
Cancel-Lock: sha1:RLRwZykyV1cvS/UbAprPGkFgzbE=
	sha1:QhS8tG7pk8UhohwU9Dw+yK4zJaQ=
Bytes: 3099

Jeroen Belleman <jeroen@nospam.please> wrote:
> On 11/12/24 16:49, john larkin wrote:
>> On Tue, 12 Nov 2024 07:49:13 -0500, legg <legg@nospam.magma.ca> wrote:
>> 
>>> On Sat, 09 Nov 2024 06:08:40 -0800, john larkin <JL@gct.com> wrote:
>>> 
>>>> 
>>>> 
>>>> Inductors are awful. Their energy storage is worse than electrolytic
>>>> caps by about a factor of 1000.
>>>> 
>>>> https://electronics.stackexchange.com/questions/326177/energy-density-comparison-between-inductors-and-capacitors
>>>> 
>>>> One could in theory make a switchmode gyrator that would make a
>>>> capacitor look like a programmable-value inductor.
>>>> 
>>>> I have an application for that, but it would take too much engineering
>>>> and runtime complexity to make it worth doing. I guess I'll just have
>>>> to buy a bunch of giant, heavy custom toroids.
>>> 
>>> I'm sure that there are other reasons why an inductor
>>> will be used besides the lack of time/energy/resources
>>> to 'design them out'.
>>> 
>>> Energy storage is just one means to an end.
>>> 
>>> RL
>> 
>> Sure. We want to design some dummy loads that will simulate relays,
>> solenoids, stepper motors, torque motors, with programmable R and L.
>> Seemed to me that using caps to make fake inductors would be a good
>> way to do that.
>> 
>> It's at least an interesting idea to play with. Maybe we can
>> switchmode simulate R+L all at once. We would have to store energy and
>> dissipate power to do that.
> 
> Relays and motors do not behave like simple inductors. For example,
> while a relay armature is moving, the back EMF is high enough to
> make the current _drop_ briefly. Modelling that requires more than
> a simple gyrator.
> 
> Jeroen Belleman
> 
> 

PM DC motors look capacitive over a broad frequency range. 

Cheers 

Phil Hobbs 

-- 
Dr Philip C D Hobbs  Principal Consultant  ElectroOptical Innovations LLC /
Hobbs ElectroOptics  Optics, Electro-optics, Photonics, Analog Electronics